## Multi Block Election Pallet

This PR adds the first iteration of the multi-block staking pallet. 

From this point onwards, the staking and its election provider pallets
are being customized to work in AssetHub. While usage in solo-chains is
still possible, it is not longer the main focus of this pallet. For a
safer usage, please fork and user an older version of this pallet.

---

## Replaces

- [x] https://github.com/paritytech/polkadot-sdk/pull/6034 
- [x] https://github.com/paritytech/polkadot-sdk/pull/5272

## Related PRs: 

- [x] https://github.com/paritytech/polkadot-sdk/pull/7483
- [ ] https://github.com/paritytech/polkadot-sdk/pull/7357
- [ ] https://github.com/paritytech/polkadot-sdk/pull/7424
- [ ] https://github.com/paritytech/polkadot-staking-miner/pull/955

This branch can be periodically merged into
https://github.com/paritytech/polkadot-sdk/pull/7358 ->
https://github.com/paritytech/polkadot-sdk/pull/6996

## TODOs: 

- [x] rebase to master 
- Benchmarking for staking critical path
  - [x] snapshot
  - [x] election result
- Benchmarking for EPMB critical path
  - [x] snapshot
  - [x] verification
  - [x] submission
  - [x] unsigned submission
  - [ ] election results fetching
- [ ] Fix deletion weights. Either of
  - [ ] Garbage collector + lazy removal of all paged storage items
  - [ ] Confirm that deletion is small PoV footprint.
- [ ] Move election prediction to be push based. @tdimitrov 
- [ ] integrity checks for bounds 
- [ ] Properly benchmark this as a part of CI -- for now I will remove
them as they are too slow
- [x] add try-state to all pallets
- [x] Staking to allow genesis dev accounts to be created internally
- [x] Decouple miner config so @niklasad1 can work on the miner
72841b73
- [x] duplicate snapshot page reported by @niklasad1

 
- [ ] https://github.com/paritytech/polkadot-sdk/pull/6520 or equivalent
-- during snapshot, `VoterList` must be locked
- [ ] Move target snapshot to a separate block

---------

Co-authored-by: Gonçalo Pestana <g6pestana@gmail.com>
Co-authored-by: Ankan <10196091+Ank4n@users.noreply.github.com>
Co-authored-by: command-bot <>
Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>
Co-authored-by: Giuseppe Re <giuseppe.re@parity.io>
Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>