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/collator-protocol/src/lib.rs

@@ -20,7 +20,6 @@
 #![deny(missing_docs, unused_crate_dependencies)]
 #![recursion_limit="256"]
 
-use std::time::Duration;
 use futures::{channel::oneshot, FutureExt, TryFutureExt};
 use thiserror::Error;
 
@@ -44,7 +43,6 @@ mod collator_side;
 mod validator_side;
 
 const LOG_TARGET: &'static str = "parachain::collator-protocol";
-const REQUEST_TIMEOUT: Duration = Duration::from_secs(1);
 
 #[derive(Debug, Error)]
 enum Error {
@@ -94,7 +92,6 @@ impl CollatorProtocolSubsystem {
 		match self.protocol_side {
 			ProtocolSide::Validator(metrics) => validator_side::run(
 				ctx,
-				REQUEST_TIMEOUT,
 				metrics,
 			).await,
 			ProtocolSide::Collator(id, metrics) => collator_side::run(
@@ -129,7 +126,7 @@ where
 #[tracing::instrument(level = "trace", skip(ctx), fields(subsystem = LOG_TARGET))]
 async fn modify_reputation<Context>(ctx: &mut Context, peer: PeerId, rep: Rep)
 where
-	Context: SubsystemContext<Message = CollatorProtocolMessage>,
+	Context: SubsystemContext,
 {
 	tracing::trace!(
 		target: LOG_TARGET,