Request based collation fetching (#2621)

* 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 !

polkadot/node/network/protocol/Cargo.toml

@@ -12,8 +12,4 @@ polkadot-node-jaeger = { path = "../../jaeger" }
 parity-scale-codec = { version = "2.0.0", default-features = false, features = ["derive"] }
 sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }
 strum = { version = "0.20", features = ["derive"] }
-thiserror = "1.0.23"
 futures = "0.3.12"
-
-[target.'cfg(not(target_os = "unknown"))'.dependencies]
-zstd = "0.5.0"