* some fixes to please cargo-spellcheck

* some (not all) fixes for the impl guide

* fix

* Only send one collation per relay parent at a time to validators

This changes the way we are sending collations to validators. Before we
answered every collation request immediatley. Now we only answer one
pov request at a time per relay parent. This should bring down the
bandwidth requirements and should help parachains to include bigger
blocks more easily.

* Guide updates

* Review feedback.

* Create validator_side module

* Subsume Candidate Selection

* Add test to ensure candidate backing logic is correct

* Ensure secondings are adequately cleaned up and address test flakyness

* Address Feedback

* guide: declare one para as a collator

* add ParaId to Declare messages and clean up

* fix build

* fix the testerinos

* begin adding keystore to collator-protocol

* remove request_x_ctx

* add core_for_group

* add bump_rotation

* add some more helpers to subsystem-util

* change signing_key API to take ref

* determine current and next para assignments

* disconnect collators who are not on current or next para

* add collator peer count metric

* notes for later

* some fixes

* add data & keystore to test state

* add a test utility for answering runtime API requests

* fix existing collator tests

* add new tests

* remove sc_keystore

* update cargo lock

Co-authored-by: Andronik Ordian <write@reusable.software>

* Introduce collation fetching protocol

also move to mod.rs

* Allow `PeerId`s in requests to network bridge.

* Fix availability distribution tests.

* Move CompressedPoV to primitives.

* Request based collator protocol: validator side

- Missing: tests
- Collator side
- don't connect, if not connected

* Fixes.

* Basic request based collator side.

* Minor fix on collator side.

* Don't connect in requests in collation protocol.

Also some cleanup.

* Fix PoV distribution

* Bump substrate

* Add back metrics + whitespace fixes.

* Add back missing spans.

* More cleanup.

* Guide update.

* Fix tests

* Handle results in tests.

* Fix weird compilation issue.

* Add missing )

* Get rid of dead code.

* Get rid of redundant import.

* Fix runtime build.

* Cleanup.

* Fix wasm build.

* Format fixes.

Thanks @andronik !

* Notify collators about seconded collation

This pr adds functionality to inform a collator that its collation was
seconded by a parachain validator. Before this signed statement was only
gossiped over the validation substream. Now, we explicitly send the
seconded statement to the collator after it was validated successfully.

Besides that it changes the `CollatorFn` to return an optional result
sender that is informed when the build collation was seconded by a
parachain validator.

* Add test

* Make sure we only send `Seconded` statements

* Make sure we only receive valid statements

* Review feedback

* collation-generation: use persisted validation data

* node: remote FullValidationData API

* runtime: remove FullValidationData API

* backing tests: use persisted validation data

* FullCandidateReceipt: use persisted validation data

This is not a big change since this type is not used anywhere

* Remove ValidationData and TransientValidationData

Also update the guide

* Introduce CollatorFn type alias

* Make test-runtime imports consistent with rococo-runtime

* Update node/primitives/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* fix warnings

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

This pr changes the collation function to also pass the current relay
parent the parachain block should be build on.

This pr changes the collator interface function to return an optional
collation instead of a collation. This is required as the parachain
itself can fail to generate a valid collation for various reason. Now if
the collation fails it will return `None`.

Besides that the pr adds some `RuntimeDebug` derive for `ValidationData`
and removes some whitespaces.

* Guide: Change for {Global,Local}ValidationData to ValidationData

Seems like that was missed during the transition from notions of global and local validation data to persistent and transient

* collation-generation: a small drive-by fix of line length

* collation-generation: extract an error module

this allows us to avoid piling Error and Result types from different contexts, specifically std vs. module-local

* collation-generation: extract LOG_TARGET from log statements

* choose the straightforward candidate selection algorithm for now

* add draft implementation of candidate selection

* fix typo in summary

* more properly report misbehaving collators

* describe how CandidateSelection subsystem becomes aware of candidates

* revise candidate selection / collator protocol interaction pattern

* implement rest of candidate selection per the guide

* review: resolve nits

* start writing test suite, harness

* implement first test

* add second test

* implement third test

Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>

* start sketching out a collation generation subsystem

* invent a basic strategy for double initialization

* clean up warnings

* impl util requests from runtime assuming a context instead of a FromJob sender

* implement collation generation algorithm from guide

* update AllMessages in tests

* fix trivial review comments

* remove another redundant declaration from merge

* filter availability cores by para_id

* handle new activations each in their own async task

* update guide according to the actual current implementation

* add initialization to guide

* add general-purpose subsystem_test_harness helper

* write first handle_new_activations test

* add test that handle_new_activations filters local_validation_data requests

* add (failing) test of collation distribution message sending

* rustfmt

* broken: work on fixing sender test

Unfortunately, for reasons that are not yet clear, despite the public key
and checked data being identical, the signer is not producing an identical
signature. This commit produces this output (among more):

signing with  Public(c4733ab0bbe3ba4c096685d1737a7f498cdbdd167a767d04a21dc7df12b8c858 (5GWHUNm5...))
checking with Public(c4733ab0bbe3ba4c096685d1737a7f498cdbdd167a767d04a21dc7df12b8c858 (5GWHUNm5...))
signed payload:  [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 10, 0, 0, 0, c7, e5, c0, 64, 7a, db, fe, 44, 81, e5, 51, 11, 79, 9f, a5, 63, 93, 94, 3c, c4, 36, c6, 30, 36, c2, c5, 44, a2, 1b, db, b7, 82, 3, 17, a, 2e, 75, 97, b7, b7, e3, d8, 4c, 5, 39, 1d, 13, 9a, 62, b1, 57, e7, 87, 86, d8, c0, 82, f2, 9d, cf, 4c, 11, 13, 14]
checked payload: [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 10, 0, 0, 0, c7, e5, c0, 64, 7a, db, fe, 44, 81, e5, 51, 11, 79, 9f, a5, 63, 93, 94, 3c, c4, 36, c6, 30, 36, c2, c5, 44, a2, 1b, db, b7, 82, 3, 17, a, 2e, 75, 97, b7, b7, e3, d8, 4c, 5, 39, 1d, 13, 9a, 62, b1, 57, e7, 87, 86, d8, c0, 82, f2, 9d, cf, 4c, 11, 13, 14]

* fix broken test

* collation function returns commitments hash

It doesn't look like we use the actual commitments data anywhere, and
it's not obvious if there are any fields of `CandidateCommitments`
not available to the collator, so this commit just assigns them the
entire responsibility of generating the hash.

* add missing overseer impls

* calculating erasure coding is polkadot's responsibility, not cumulus

* concurrentize per-relay_parent requests

* guide: validation data refactoring

* address grumbles from review

* Update roadmap/implementers-guide/src/types/candidate.md

Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>

* last comments from review

Co-authored-by: Sergei Shulepov <sergei@parity.io>
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>

* rename protocol ID to network capability

* guide: `ProtocolId` -> `NetworkCapability`

* guide: remove `RegisterEventProducer`

* capabilities and expand on underlying network assumptions

* guide: create network.md types file

* guide: network bridge is aware of network messages

* revert changes in code

* Update roadmap/implementers-guide/src/SUMMARY.md

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

* remove references to NetworkCapability

* Update roadmap/implementers-guide/src/types/network.md

Co-authored-by: Sergei Shulepov <sergei@parity.io>

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>
Co-authored-by: Sergei Shulepov <sergei@parity.io>

* Do a small write-up on collation-generation

* preamble to collator protocol

* notes on protocol

* collation-generation: point to collator protocol

* fix missing bracket

* expand on collator protocol wire protocol

* add a couple more sentences

* expand on requests some more

* go higher level

* network bridge: note peerset

* note peer-set = validation for protocols

* add `ConnectToValidators` message

* use ConnectToValidators in collator protocol

* typo

* remove references to sentry nodes

* rename implementor's guide to implementer's guide

* fix typos in more places