supersedes https://github.com/paritytech/parity-bridges-common/pull/2873

Draft because of couple of TODOs:
- [x] fix remaining TODOs;
- [x] double check that all changes from
https://github.com/paritytech/parity-bridges-common/pull/2873 are
correctly ported;
- [x] create a separate PR (on top of that one or a follow up?) for
https://github.com/paritytech/polkadot-sdk/tree/sv-try-new-bridge-fees;


- [x] fix compilation issues (haven't checked, but there should be
many).

---------

Co-authored-by: Adrian Catangiu <[email protected]>

Enables pov-reclaim on the rococo/westend parachains, part of
https://github.com/paritytech/polkadot-sdk/issues/3622

Introduces `CryptoBytes` type defined as:

```rust
pub struct CryptoBytes<const N: usize, Tag = ()>(pub [u8; N], PhantomData<fn() -> Tag>);
```

The type implements a bunch of methods and traits which are typically
expected from a byte array newtype
(NOTE: some of the methods and trait implementations IMO are a bit
redundant, but I decided to maintain them all to not change too much
stuff in this PR)

It also introduces two (generic) typical consumers of `CryptoBytes`:
`PublicBytes` and `SignatureBytes`.

```rust
pub struct PublicTag;
pub PublicBytes<const N: usize, CryptoTag> = CryptoBytes<N, (PublicTag, CryptoTag)>;

pub struct SignatureTag;
pub SignatureBytes<const N: usize, CryptoTag> = CryptoBytes<N, (SignatureTag, CryptoTag)>;
```

Both of them use a tag to differentiate the two types at a higher level.
Downstream specializations will further specialize using a dedicated
crypto tag. For example in ECDSA:


```rust
pub struct EcdsaTag;

pub type Public = PublicBytes<PUBLIC_KEY_SERIALIZED_SIZE, EcdsaTag>;
pub type Signature = PublicBytes<PUBLIC_KEY_SERIALIZED_SIZE, EcdsaTag>;
```

Overall we have a cleaner and most importantly **consistent** code for
all the types involved

All these details are opaque to the end user which can use `Public` and
`Signature` for the cryptos as before

Revert "FRAME: Create `TransactionExtension` as a replacement for `SignedExtension` (#2280)" (#3665)

This PR reverts #2280 which introduced `TransactionExtension` to replace
`SignedExtension`.

As a result of the discussion
[here](https://github.com/paritytech/polkadot-sdk/pull/3623#issuecomment-1986789700

),
the changes will be reverted for now with plans to reintroduce the
concept in the future.

---------

Signed-off-by: georgepisaltu <[email protected]>

Closes #2160

First part of [Extrinsic
Horizon](https://github.com/paritytech/polkadot-sdk/issues/2415

)

Introduces a new trait `TransactionExtension` to replace
`SignedExtension`. Introduce the idea of transactions which obey the
runtime's extensions and have according Extension data (né Extra data)
yet do not have hard-coded signatures.

Deprecate the terminology of "Unsigned" when used for
transactions/extrinsics owing to there now being "proper" unsigned
transactions which obey the extension framework and "old-style" unsigned
which do not. Instead we have __*General*__ for the former and
__*Bare*__ for the latter. (Ultimately, the latter will be phased out as
a type of transaction, and Bare will only be used for Inherents.)

Types of extrinsic are now therefore:
- Bare (no hardcoded signature, no Extra data; used to be known as
"Unsigned")
- Bare transactions (deprecated): Gossiped, validated with
`ValidateUnsigned` (deprecated) and the `_bare_compat` bits of
`TransactionExtension` (deprecated).
  - Inherents: Not gossiped, validated with `ProvideInherent`.
- Extended (Extra data): Gossiped, validated via `TransactionExtension`.
  - Signed transactions (with a hardcoded signature).
  - General transactions (without a hardcoded signature).

`TransactionExtension` differs from `SignedExtension` because:
- A signature on the underlying transaction may validly not be present.
- It may alter the origin during validation.
- `pre_dispatch` is renamed to `prepare` and need not contain the checks
present in `validate`.
- `validate` and `prepare` is passed an `Origin` rather than a
`AccountId`.
- `validate` may pass arbitrary information into `prepare` via a new
user-specifiable type `Val`.
- `AdditionalSigned`/`additional_signed` is renamed to
`Implicit`/`implicit`. It is encoded *for the entire transaction* and
passed in to each extension as a new argument to `validate`. This
facilitates the ability of extensions to acts as underlying crypto.

There is a new `DispatchTransaction` trait which contains only default
function impls and is impl'ed for any `TransactionExtension` impler. It
provides several utility functions which reduce some of the tedium from
using `TransactionExtension` (indeed, none of its regular functions
should now need to be called directly).

Three transaction version discriminator ("versions") are now
permissible:
- 0b000000100: Bare (used to be called "Unsigned"): contains Signature
or Extra (extension data). After bare transactions are no longer
supported, this will strictly identify an Inherents only.
- 0b100000100: Old-school "Signed" Transaction: contains Signature and
Extra (extension data).
- 0b010000100: New-school "General" Transaction: contains Extra
(extension data), but no Signature.

For the New-school General Transaction, it becomes trivial for authors
to publish extensions to the mechanism for authorizing an Origin, e.g.
through new kinds of key-signing schemes, ZK proofs, pallet state,
mutations over pre-authenticated origins or any combination of the
above.

## Code Migration

### NOW: Getting it to build

Wrap your `SignedExtension`s in `AsTransactionExtension`. This should be
accompanied by renaming your aggregate type in line with the new
terminology. E.g. Before:

```rust
/// The SignedExtension to the basic transaction logic.
pub type SignedExtra = (
	/* snip */
	MySpecialSignedExtension,
);
/// Unchecked extrinsic type as expected by this runtime.
pub type UncheckedExtrinsic =
	generic::UncheckedExtrinsic<Address, RuntimeCall, Signature, SignedExtra>;
```

After:

```rust
/// The extension to the basic transaction logic.
pub type TxExtension = (
	/* snip */
	AsTransactionExtension<MySpecialSignedExtension>,
);
/// Unchecked extrinsic type as expected by this runtime.
pub type UncheckedExtrinsic =
	generic::UncheckedExtrinsic<Address, RuntimeCall, Signature, TxExtension>;
```

You'll also need to alter any transaction building logic to add a
`.into()` to make the conversion happen. E.g. Before:

```rust
fn construct_extrinsic(
		/* snip */
) -> UncheckedExtrinsic {
	let extra: SignedExtra = (
		/* snip */
		MySpecialSignedExtension::new(/* snip */),
	);
	let payload = SignedPayload::new(call.clone(), extra.clone()).unwrap();
	let signature = payload.using_encoded(|e| sender.sign(e));
	UncheckedExtrinsic::new_signed(
		/* snip */
		Signature::Sr25519(signature),
		extra,
	)
}
```

After:

```rust
fn construct_extrinsic(
		/* snip */
) -> UncheckedExtrinsic {
	let tx_ext: TxExtension = (
		/* snip */
		MySpecialSignedExtension::new(/* snip */).into(),
	);
	let payload = SignedPayload::new(call.clone(), tx_ext.clone()).unwrap();
	let signature = payload.using_encoded(|e| sender.sign(e));
	UncheckedExtrinsic::new_signed(
		/* snip */
		Signature::Sr25519(signature),
		tx_ext,
	)
}
```

### SOON: Migrating to `TransactionExtension`

Most `SignedExtension`s can be trivially converted to become a
`TransactionExtension`. There are a few things to know.

- Instead of a single trait like `SignedExtension`, you should now
implement two traits individually: `TransactionExtensionBase` and
`TransactionExtension`.
- Weights are now a thing and must be provided via the new function `fn
weight`.

#### `TransactionExtensionBase`

This trait takes care of anything which is not dependent on types
specific to your runtime, most notably `Call`.

- `AdditionalSigned`/`additional_signed` is renamed to
`Implicit`/`implicit`.
- Weight must be returned by implementing the `weight` function. If your
extension is associated with a pallet, you'll probably want to do this
via the pallet's existing benchmarking infrastructure.

#### `TransactionExtension`

Generally:
- `pre_dispatch` is now `prepare` and you *should not reexecute the
`validate` functionality in there*!
- You don't get an account ID any more; you get an origin instead. If
you need to presume an account ID, then you can use the trait function
`AsSystemOriginSigner::as_system_origin_signer`.
- You get an additional ticket, similar to `Pre`, called `Val`. This
defines data which is passed from `validate` into `prepare`. This is
important since you should not be duplicating logic from `validate` to
`prepare`, you need a way of passing your working from the former into
the latter. This is it.
- This trait takes two type parameters: `Call` and `Context`. `Call` is
the runtime call type which used to be an associated type; you can just
move it to become a type parameter for your trait impl. `Context` is not
currently used and you can safely implement over it as an unbounded
type.
- There's no `AccountId` associated type any more. Just remove it.

Regarding `validate`:
- You get three new parameters in `validate`; all can be ignored when
migrating from `SignedExtension`.
- `validate` returns a tuple on success; the second item in the tuple is
the new ticket type `Self::Val` which gets passed in to `prepare`. If
you use any information extracted during `validate` (off-chain and
on-chain, non-mutating) in `prepare` (on-chain, mutating) then you can
pass it through with this. For the tuple's last item, just return the
`origin` argument.

Regarding `prepare`:
- This is renamed from `pre_dispatch`, but there is one change:
- FUNCTIONALITY TO VALIDATE THE TRANSACTION NEED NOT BE DUPLICATED FROM
`validate`!!
- (This is different to `SignedExtension` which was required to run the
same checks in `pre_dispatch` as in `validate`.)

Regarding `post_dispatch`:
- Since there are no unsigned transactions handled by
`TransactionExtension`, `Pre` is always defined, so the first parameter
is `Self::Pre` rather than `Option<Self::Pre>`.

If you make use of `SignedExtension::validate_unsigned` or
`SignedExtension::pre_dispatch_unsigned`, then:
- Just use the regular versions of these functions instead.
- Have your logic execute in the case that the `origin` is `None`.
- Ensure your transaction creation logic creates a General Transaction
rather than a Bare Transaction; this means having to include all
`TransactionExtension`s' data.
- `ValidateUnsigned` can still be used (for now) if you need to be able
to construct transactions which contain none of the extension data,
however these will be phased out in stage 2 of the Transactions Horizon,
so you should consider moving to an extension-centric design.

## TODO

- [x] Introduce `CheckSignature` impl of `TransactionExtension` to
ensure it's possible to have crypto be done wholly in a
`TransactionExtension`.
- [x] Deprecate `SignedExtension` and move all uses in codebase to
`TransactionExtension`.
  - [x] `ChargeTransactionPayment`
  - [x] `DummyExtension`
  - [x] `ChargeAssetTxPayment` (asset-tx-payment)
  - [x] `ChargeAssetTxPayment` (asset-conversion-tx-payment)
  - [x] `CheckWeight`
  - [x] `CheckTxVersion`
  - [x] `CheckSpecVersion`
  - [x] `CheckNonce`
  - [x] `CheckNonZeroSender`
  - [x] `CheckMortality`
  - [x] `CheckGenesis`
  - [x] `CheckOnlySudoAccount`
  - [x] `WatchDummy`
  - [x] `PrevalidateAttests`
  - [x] `GenericSignedExtension`
  - [x] `SignedExtension` (chain-polkadot-bulletin)
  - [x] `RefundSignedExtensionAdapter`
- [x] Implement `fn weight` across the board.
- [ ] Go through all pre-existing extensions which assume an account
signer and explicitly handle the possibility of another kind of origin.
- [x] `CheckNonce` should probably succeed in the case of a non-account
origin.
- [x] `CheckNonZeroSender` should succeed in the case of a non-account
origin.
- [x] `ChargeTransactionPayment` and family should fail in the case of a
non-account origin.
  - [ ] 
- [x] Fix any broken tests.

---------

Signed-off-by: georgepisaltu <[email protected]>
Signed-off-by: Alexandru Vasile <[email protected]>
Signed-off-by: dependabot[bot] <[email protected]>
Signed-off-by: Oliver Tale-Yazdi <[email protected]>
Signed-off-by: Alexandru Gheorghe <[email protected]>
Signed-off-by: Andrei Sandu <[email protected]>
Co-authored-by: Nikhil Gupta <[email protected]>
Co-authored-by: georgepisaltu <[email protected]>
Co-authored-by: Chevdor <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: Maciej <[email protected]>
Co-authored-by: Javier Viola <[email protected]>
Co-authored-by: Marcin S. <[email protected]>
Co-authored-by: Tsvetomir Dimitrov <[email protected]>
Co-authored-by: Javier Bullrich <[email protected]>
Co-authored-by: Koute <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>
Co-authored-by: Vladimir Istyufeev <[email protected]>
Co-authored-by: Ross Bulat <[email protected]>
Co-authored-by: Gonçalo Pestana <[email protected]>
Co-authored-by: Liam Aharon <[email protected]>
Co-authored-by: Svyatoslav Nikolsky <[email protected]>
Co-authored-by: André Silva <[email protected]>
Co-authored-by: Oliver Tale-Yazdi <[email protected]>
Co-authored-by: s0me0ne-unkn0wn <[email protected]>
Co-authored-by: ordian <[email protected]>
Co-authored-by: Sebastian Kunert <[email protected]>
Co-authored-by: Aaro Altonen <[email protected]>
Co-authored-by: Dmitry Markin <[email protected]>
Co-authored-by: Alexandru Vasile <[email protected]>
Co-authored-by: Alexander Samusev <[email protected]>
Co-authored-by: Julian Eager <[email protected]>
Co-authored-by: Michal Kucharczyk <[email protected]>
Co-authored-by: Davide Galassi <[email protected]>
Co-authored-by: Dónal Murray <[email protected]>
Co-authored-by: yjh <[email protected]>
Co-authored-by: Tom Mi <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Will | Paradox | ParaNodes.io <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: Joshy Orndorff <[email protected]>
Co-authored-by: Joshy Orndorff <[email protected]>
Co-authored-by: PG Herveou <[email protected]>
Co-authored-by: Alexander Theißen <[email protected]>
Co-authored-by: Kian Paimani <[email protected]>
Co-authored-by: Juan Girini <[email protected]>
Co-authored-by: bader y <[email protected]>
Co-authored-by: James Wilson <[email protected]>
Co-authored-by: joe petrowski <[email protected]>
Co-authored-by: asynchronous rob <[email protected]>
Co-authored-by: Parth <[email protected]>
Co-authored-by: Andrew Jones <[email protected]>
Co-authored-by: Jonathan Udd <[email protected]>
Co-authored-by: Serban Iorga <[email protected]>
Co-authored-by: Egor_P <[email protected]>
Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: Evgeny Snitko <[email protected]>
Co-authored-by: Just van Stam <[email protected]>
Co-authored-by: Francisco Aguirre <[email protected]>
Co-authored-by: gupnik <[email protected]>
Co-authored-by: dzmitry-lahoda <[email protected]>
Co-authored-by: zhiqiangxu <[email protected]>
Co-authored-by: Nazar Mokrynskyi <[email protected]>
Co-authored-by: Anwesh <[email protected]>
Co-authored-by: cheme <[email protected]>
Co-authored-by: Sam Johnson <[email protected]>
Co-authored-by: kianenigma <[email protected]>
Co-authored-by: Jegor Sidorenko <[email protected]>
Co-authored-by: Muharem <[email protected]>
Co-authored-by: joepetrowski <[email protected]>
Co-authored-by: Alexandru Gheorghe <[email protected]>
Co-authored-by: Gabriel Facco de Arruda <[email protected]>
Co-authored-by: Squirrel <[email protected]>
Co-authored-by: Andrei Sandu <[email protected]>
Co-authored-by: georgepisaltu <[email protected]>
Co-authored-by: command-bot <>

Built on top of https://github.com/paritytech/polkadot-sdk/pull/2826/
which was a trial run.

Guide:
https://github.com/w3f/polkadot-wiki/blob/master/docs/maintain/maintain-guides-async-backing.md



---------

Signed-off-by: georgepisaltu <[email protected]>
Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: Dónal Murray <[email protected]>
Co-authored-by: Dmitry Sinyavin <[email protected]>
Co-authored-by: s0me0ne-unkn0wn <[email protected]>
Co-authored-by: Svyatoslav Nikolsky <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: georgepisaltu <[email protected]>

## TODO
- [x] change constants when CI fails (should fail :) )

## Result

On the AssetHubRococo: 1701175800126 -> 1700929825257 = 0.15 %
decreased.
```
# Before ( [xcm] Fix `SovereignPaidRemoteExporter` and `DepositAsset` handling (#3157))
Feb 02 12:59:05.520 ERROR bridges::estimate: `bridging::XcmBridgeHubRouterBaseFee` actual value: 1701175800126 for runtime: statemine-1006000 (statemine-0.tx14.au1)    

# After
Feb 02 13:02:40.647 ERROR bridges::estimate: `bridging::XcmBridgeHubRouterBaseFee` actual value: 1700929825257 for runtime: statemine-1006000 (statemine-0.tx14.au1)    

```

On the AssetHubWestend: 2116038876326 -> 1641718372993 = 22.4 %
decreased.
```
# Before ( [xcm] Fix `SovereignPaidRemoteExporter` and `DepositAsset` handling (#3157))
Feb 02 12:56:00.880 ERROR bridges::estimate: `bridging::XcmBridgeHubRouterBaseFee` actual value: 2116038876326 for runtime: westmint-1006000 (westmint-0.tx14.au1)    


# After
Feb 02 13:04:42.515 ERROR bridges::estimate: `bridging::XcmBridgeHubRouterBaseFee` actual value: 1641718372993 for runtime: westmint-1006000 (westmint-0.tx14.au1)    
```

The `parachains-common` contains a lots of constants and type
definitions which are used for `polkadot-sdk`'s testnet runtimes and
also for `polkadot-fellows`'s production [SP
runtimes](https://github.com/polkadot-fellows/runtimes/tree/main/system-parachains/constants).
This PR cleans `parachains-common` module to contain only common and
generic functionality.

Testnet-specific constants have been moved to the separate module
dedicated just for testnets:
`polkadot-sdk/cumulus/parachains/runtimes/constants/`


Part of: https://github.com/paritytech/polkadot-sdk/issues/3054



---------

Co-authored-by: georgepisaltu <[email protected]>

The goal is to move all system chains on Rococo (+ other testnets?) to
use async backing.

Starting with `asset-hub-rococo` to get feedback, before I do the rest.

## Related

Example: https://github.com/paritytech/polkadot-sdk/pull/1619/
Guide:
https://github.com/w3f/polkadot-wiki/blob/master/docs/maintain/maintain-guides-async-backing.md



---------

Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: Dónal Murray <[email protected]>

# Note for reviewer

Most changes are just syntax changes necessary for the new version.
Most important files should be the ones under the `xcm` folder.

# Description 

Added XCMv4.

## Removed `Multi` prefix
The following types have been renamed:
- MultiLocation -> Location
- MultiAsset -> Asset
- MultiAssets -> Assets
- InteriorMultiLocation -> InteriorLocation
- MultiAssetFilter -> AssetFilter
- VersionedMultiAsset -> VersionedAsset
- WildMultiAsset -> WildAsset
- VersionedMultiLocation -> VersionedLocation

In order to fix a name conflict, the `Assets` in `xcm-executor` were
renamed to `HoldingAssets`, as they represent assets in holding.

## Removed `Abstract` asset id

It was not being used anywhere and this simplifies the code.

Now assets are just constructed as follows:

```rust
let asset: Asset = (AssetId(Location::new(1, Here)), 100u128).into();
```

No need for specifying `Concrete` anymore.

## Outcome is now a named fields struct

Instead of

```rust
pub enum Outcome {
  Complete(Weight),
  Incomplete(Weight, Error),
  Error(Error),
}
```

we now have

```rust
pub enum Outcome {
  Complete { used: Weight },
  Incomplete { used: Weight, error: Error },
  Error { error: Error },
}
```

## Added Reanchorable trait

Now both locations and assets implement this trait, making it easier to
reanchor both.

## New syntax for building locations and junctions

Now junctions are built using the following methods:

```rust
let location = Location {
    parents: 1,
    interior: [Parachain(1000), PalletInstance(50), GeneralIndex(1984)].into()
};
```

or

```rust
let location = Location::new(1, [Parachain(1000), PalletInstance(50), GeneralIndex(1984)]);
```

And they are matched like so:

```rust
match location.unpack() {
  (1, [Parachain(id)]) => ...
  (0, Here) => ...,
  (1, [_]) => ...,
}
```

This syntax is mandatory in v4, and has been also implemented for v2 and
v3 for easier migration.

This was needed to make all sizes smaller.

# TODO
- [x] Scaffold v4
- [x] Port github.com/paritytech/polkadot/pull/7236
- [x] Remove `Multi` prefix
- [x] Remove `Abstract` asset id

---------

Co-authored-by: command-bot <>
Co-authored-by: Keith Yeung <[email protected]>

related to
https://github.com/paritytech/parity-bridges-common/issues/2739

This PR adds possibility for relay chain governance to halt and resume
bridge pallets using XCM calls. Following calls are enabled over XCM for
the `root` origin: `pallet_bridge_grandpa::set_operating_mode`,
`pallet_bridge_parachains::set_operating_mode` and
`pallet_bridge_messages::set_operating_mode`.

So far the `bridge-hub-test-utils` contained a tests set for testing
BridgeHub runtime that is bridging with the remote **parachain**. But we
have https://github.com/paritytech/polkadot-sdk/pull/2540 coming, which
would add Rococo <> Bulletin chain bridge (where Bulletin = standalone
chain that is using GRANDPA finality). Then it'll be expanded to
Polkadot BH as well.

So this PR adds the same set of tests to the `bridge-hub-test-utils`,
but for the case when remote chain is the chain with GRANDPA finality.
There's a lot of changes in this PR - I'll describe some:
- I've added `BasicParachainRuntime` trait to decrease number of lines
we need to add to `where` clause. Could revert, but imo it is useful;
- `cumulus/parachains/runtimes/bridge-hubs/test-utils/src/test_data` is
a submodule for generating test data for the test sets.
`from_parachain.rs` is used in tests for the case when remote chain is a
parachain, `from_grandpa_chain.rs` - for the bridges with remote GRANDPA
chains. `mod.rs` has some code, shared by both types of tests;
- `cumulus/parachains/runtimes/bridge-hubs/test-utils/src/test_data` is
a submodule with all test cases. The `mod.rs` has tests, suitable for
all cases. There's also `wth_parachain.rs` and `with_grandpa_chain.rs`
with the same meaning as above;
- I've merged the "core" code of two previous tests -
`relayed_incoming_message_works` and `complex_relay_extrinsic_works`
into one single `relayed_incoming_message_works` test. So now we are
always constructing extrinsics and are dispatching them using executive
module (meaning all signed extensions are also tested).

New test set is used here:
https://github.com/paritytech/polkadot-sdk/pull/2540. Once this PR is
merged, I'll merge that other PR with master to remove duplicate
changes.

I'm also planning to cleanup generic constraints + remove some
unnecessary assumptions about used chains in a follow-up PRs. But for
now I think this PR has enough changes, so don't want to complicate it
even more.

---

Breaking changes for the code that have used those tests before:
- the `construct_and_apply_extrinsic` callback now accepts the
`RuntimeCall` instead of the `pallet_utility::Call`;
- the `construct_and_apply_extrinsic` now may be called multiple times
for the single test, so make sure the `frame_system::CheckNonce` is
correctly constructed;
- all previous tests have been moved from
`bridge_hub_test_utils::test_cases` to
`bridge_hub_test_utils::test_cases::from_parachain` module;
- there are several changes in test arguments - please refer to
https://github.com/paritytech/polkadot-sdk/compare/sv-tests-for-bridge-with-remote-grandpa-chain?expand=1#diff-79a28d4d3e1749050341c2424f00c4c139825b1a20937767f83e58b95166735c
for details.

## Summary

This pull request proposes a solution for improved control of the
versioned XCM flow over the bridge (across different consensus chains)
and resolves the situation where the sending chain/consensus has already
migrated to a higher XCM version than the receiving chain/consensus.

## Problem/Motivation

The current flow over the bridge involves a transfer from AssetHubRococo
(AHR) to BridgeHubRococo (BHR) to BridgeHubWestend (BHW) and finally to
AssetHubWestend (AHW), beginning with a reserve-backed transfer on AHR.

In this process:
1. AHR sends XCM `ExportMessage` through `XcmpQueue`, incorporating XCM
version checks using the `WrapVersion` feature, influenced by
`pallet_xcm::SupportedVersion` (managed by
`pallet_xcm::force_xcm_version` or version discovery).

2. BHR handles the `ExportMessage` instruction, utilizing the latest XCM
version. The `HaulBlobExporter` converts the inner XCM to
[`VersionedXcm::from`](https://github.com/paritytech/polkadot-sdk/blob/63ac2471aa0210f0ac9903bdd7d8f9351f9a635f/polkadot/xcm/xcm-builder/src/universal_exports.rs#L465-L467),
also using the latest XCM version.

However, challenges arise:
- Incompatibility when BHW uses a different version than BHR. For
instance, if BHR migrates to **XCMv4** while BHW remains on **XCMv3**,
BHR's `VersionedXcm::from` uses `VersionedXcm::V4` variant, causing
encoding issues for BHW.
  ```
	/// Just a simulation of possible error, which could happen on BHW
	/// (this code is based on actual master without XCMv4)
	let encoded = hex_literal::hex!("0400");
	println!("{:?}", VersionedXcm::<()>::decode(&mut &encoded[..]));

Err(Error { cause: None, desc: "Could not decode `VersionedXcm`, variant
doesn't exist" })
  ``` 
- Similar compatibility issues exist between AHR and AHW.

## Solution

This pull request introduces the following solutions:

1. **New trait `CheckVersion`** - added to the `xcm` module and exposing
`pallet_xcm::SupportedVersion`. This enhancement allows checking the
actual XCM version for desired destinations outside of the `pallet_xcm`
module.

2. **Version Check in `HaulBlobExporter`** uses `CheckVersion` to check
known/configured destination versions, ensuring compatibility. For
example, in the scenario mentioned, BHR can store the version `3` for
BHW. If BHR is on XCMv4, it will attempt to downgrade the message to
version `3` instead of using the latest version `4`.

3. **Version Check in `pallet-xcm-bridge-hub-router`** - this check
ensures compatibility with the real destination's XCM version,
preventing the unnecessary sending of messages to the local bridge hub
if versions are incompatible.

These additions aim to improve the control and compatibility of XCM
flows over the bridge and addressing issues related to version
mismatches.

## Possible alternative solution

_(More investigation is needed, and at the very least, it should extend
to XCMv4/5. If this proves to be a viable option, I can open an RFC for
XCM.)._

Add the `XcmVersion` attribute to the `ExportMessage` so that the
sending chain can determine, based on what is stored in
`pallet_xcm::SupportedVersion`, the version the destination is using.
This way, we may not need to handle the version in `HaulBlobExporter`.

```
ExportMessage {
	network: NetworkId,
	destination: InteriorMultiLocation,
	xcm: Xcm<()>
	destination_xcm_version: Version, // <- new attritbute
},
```

```
pub trait ExportXcm {
        fn validate(
		network: NetworkId,
		channel: u32,
		universal_source: &mut Option<InteriorMultiLocation>,
		destination: &mut Option<InteriorMultiLocation>,
		message: &mut Option<Xcm<()>>,
                destination_xcm_version: Version, , // <- new attritbute
	) -> SendResult<Self::Ticket>;
```

## Future Directions

This PR does not fix version discovery over bridge, further
investigation will be conducted here:
https://github.com/paritytech/polkadot-sdk/issues/2417.

## TODO

- [x] `pallet_xcm` mock for tests uses hard-coded XCM version `2` -
change to 3 or lastest?
- [x] fix `pallet-xcm-bridge-hub-router`
- [x] fix HaulBlobExporter with version determination
[here](https://github.com/paritytech/polkadot-sdk/blob/2183669d05f9b510f979a0cc3c7847707bacba2e/polkadot/xcm/xcm-builder/src/universal_exports.rs#L465)
- [x] add unit-tests to the runtimes
- [x] run benchmarks for `ExportMessage`
- [x] extend local run scripts about `force_xcm_version(dest, version)`
- [ ] when merged, prepare governance calls for Rococo/Westend
- [ ] add PRDoc

Part of: https://github.com/paritytech/parity-bridges-common/issues/2719

---------

Co-authored-by: command-bot <>

## Summary

This PR aligns Rococo/Westend bridge with latest Bridges repo
development:
- https://github.com/paritytech/parity-bridges-common/pull/2727
- https://github.com/paritytech/parity-bridges-common/pull/2728
- https://github.com/paritytech/parity-bridges-common/pull/2729




Part of: https://github.com/paritytech/parity-bridges-common/issues/2452

## Motivation

`pallet-xcm` is the main user-facing interface for XCM functionality,
including assets manipulation functions like `teleportAssets()` and
`reserve_transfer_assets()` calls.

While `teleportAsset()` works both ways, `reserve_transfer_assets()`
works only for sending reserve-based assets to a remote destination and
beneficiary when the reserve is the _local chain_.

## Solution

This PR enhances `pallet_xcm::(limited_)reserve_withdraw_assets` to
support transfers when reserves are other chains.
This will allow complete, **bi-directional** reserve-based asset
transfers user stories using `pallet-xcm`.

Enables following scenarios:
- transferring assets with local reserve (was previously supported iff
asset used as fee also had local reserve - now it works in all cases),
- transferring assets with reserve on destination,
- transferring assets with reserve on remote/third-party chain (iff
assets and fees have same remote reserve),
- transferring assets with reserve different than the reserve of the
asset to be used as fees - meaning can be used to transfer random asset
with local/dest reserve while using DOT for fees on all involved chains,
even if DOT local/dest reserve doesn't match asset reserve,
- transferring assets with any type of local/dest reserve while using
fees which can be teleported between involved chains.

All of the above is done by pallet inner logic without the user having
to specify which scenario/reserves/teleports/etc. The correct scenario
and corresponding XCM programs are identified, and respectively, built
automatically based on runtime configuration of trusted teleporters and
trusted reserves.

#### Current limitations:
- while `fees` and "non-fee" `assets` CAN have different reserves (or
fees CAN be teleported), the remaining "non-fee" `assets` CANNOT, among
themselves, have different reserve locations (this is also implicitly
enforced by `MAX_ASSETS_FOR_TRANSFER=2`, but this can be safely
increased in the future).
- `fees` and "non-fee" `assets` CANNOT have **different remote**
reserves (this could also be supported in the future, but adds even more
complexity while possibly not being worth it - we'll see what the future
holds).

Fixes https://github.com/paritytech/polkadot-sdk/issues/1584
Fixes https://github.com/paritytech/polkadot-sdk/issues/2055



---------

Co-authored-by: Francisco Aguirre <[email protected]>
Co-authored-by: Branislav Kontur <[email protected]>

Right now governance could only control byte-fee component of Rococo <>
Westend message fees (paid at Asset Hubs). This PR changes it a bit:
1) governance now allowed to control both fee components - byte fee and
base fee;
2) base fee now includes cost of "default" delivery and confirmation
transactions, in addition to `ExportMessage` instruction cost.

## Summary

Asset bridging support for AssetHub**Rococo** <-> AssetHub**Wococo** was
added [here](https://github.com/paritytech/polkadot-sdk/pull/1215), so
now we aim to bridge AssetHub**Rococo** and AssetHub**Westend**. (And
perhaps retire AssetHubWococo and the Wococo chains).

## Solution

**bridge-hub-westend-runtime**
- added new runtime as a copy of `bridge-hub-rococo-runtime`
- added support for bridging to `BridgeHubRococo`
- added tests and benchmarks

**bridge-hub-rococo-runtime**
- added support for bridging to `BridgeHubWestend`
- added tests and benchmarks
- internal refactoring by splitting bridge configuration per network,
e.g., `bridge_to_whatevernetwork_config.rs`.

**asset-hub-rococo-runtime**
- added support for asset bridging to `AssetHubWestend` (allows to
receive only WNDs)
- added new xcm router for `Westend`
- added tests and benchmarks

**asset-hub-westend-runtime**
- added support for asset bridging to `AssetHubRococo` (allows to
receive only ROCs)
- added new xcm router for `Rococo`
- added tests and benchmarks

## Deployment

All changes will be deployed as a part of
https://github.com/paritytech/polkadot-sdk/issues/1988.

## TODO

- [x] benchmarks for all pallet instances
- [x] integration tests
- [x] local run scripts


Relates to:
https://github.com/paritytech/parity-bridges-common/issues/2602
Relates to: https://github.com/paritytech/polkadot-sdk/issues/1988



---------

Co-authored-by: command-bot <>
Co-authored-by: Adrian Catangiu <[email protected]>
Co-authored-by: joe petrowski <[email protected]>