* add number to `ActivatedLeavesUpdate`

* update subsystem util and overseer

* use new ActivatedLeaf everywhere

* sort view

* sorted and limited view in network bridge

* use live block hash only if it's newer

* grumples

* add AvailableDataFetchingRequest

* rename AvailabilityFetchingRequest to ChunkFetchingRequest

* rename AvailabilityFetchingResponse to Chunk_

* add AvailableDataFetching request

* add available data fetching request to availability recovery message

* remove availability recovery message

* fix

* update network bridge

* port availability recovery to request/response

* use validators.len(), not shuffling

* fix availability recovery tests

* update guide

* Update node/network/availability-recovery/src/lib.rs

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

* Update node/network/availability-recovery/src/lib.rs

Co-authored-by: Arkadiy Paronyan <arkady.paronyan@gmail.com>

* remove println

Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
Co-authored-by: Arkadiy Paronyan <arkady.paronyan@gmail.com>

* 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 !

* WIP: Whole subsystem test.

* New tests compile.

* Avoid needless runtime queries for no validator nodes.

* Make tx and rx publicly accessible in virtual overseer.

This simplifies mocking in some cases, as tx can be cloned, but rx can
not.

* Whole subsystem test working.

* Update node/network/availability-distribution/src/session_cache.rs

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

* Update node/network/availability-distribution/src/session_cache.rs

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

* Document better what `None` return value means.

* Get rid of BitVec dependency.

* Update Cargo.lock

* Hopefully fixed implementers guide build.

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