Do not run unneeded subsystems on collator and its alongside node (#3061)

Currently, collators and their alongside nodes spin up a full-scale
overseer running a bunch of subsystems that are not needed if the node
is not a validator. That was considered to be harmless; however, we've
got problems with unused subsystems getting stalled for a reason not
currently known, resulting in the overseer exiting and bringing down the
whole node.

This PR aims to only run needed subsystems on such nodes, replacing the
rest with `DummySubsystem`.

It also enables collator-optimized availability recovery subsystem
implementation.

Partially solves #1730.

polkadot/node/malus/src/variants/support_disabled.rs

@@ -18,13 +18,12 @@
 //! to always return an empty set of disabled validators.
 
 use polkadot_cli::{
-	prepared_overseer_builder,
 	service::{
-		AuthorityDiscoveryApi, AuxStore, BabeApi, Block, Error, HeaderBackend, Overseer,
-		OverseerConnector, OverseerGen, OverseerGenArgs, OverseerHandle, ParachainHost,
-		ProvideRuntimeApi,
+		AuthorityDiscoveryApi, AuxStore, BabeApi, Block, Error, ExtendedOverseerGenArgs,
+		HeaderBackend, Overseer, OverseerConnector, OverseerGen, OverseerGenArgs, OverseerHandle,
+		ParachainHost, ProvideRuntimeApi,
 	},
-	Cli,
+	validator_overseer_builder, Cli,
 };
 use polkadot_node_subsystem::SpawnGlue;
 use polkadot_node_subsystem_types::DefaultSubsystemClient;
@@ -50,6 +49,7 @@ impl OverseerGen for SupportDisabled {
 		&self,
 		connector: OverseerConnector,
 		args: OverseerGenArgs<'_, Spawner, RuntimeClient>,
+		ext_args: Option<ExtendedOverseerGenArgs>,
 	) -> Result<
 		(Overseer<SpawnGlue<Spawner>, Arc<DefaultSubsystemClient<RuntimeClient>>>, OverseerHandle),
 		Error,
@@ -59,12 +59,15 @@ impl OverseerGen for SupportDisabled {
 		RuntimeClient::Api: ParachainHost<Block> + BabeApi<Block> + AuthorityDiscoveryApi<Block>,
 		Spawner: 'static + SpawnNamed + Clone + Unpin,
 	{
-		prepared_overseer_builder(args)?
-			.replace_runtime_api(move |ra_subsystem| {
-				InterceptedSubsystem::new(ra_subsystem, IgnoreDisabled)
-			})
-			.build_with_connector(connector)
-			.map_err(|e| e.into())
+		validator_overseer_builder(
+			args,
+			ext_args.expect("Extended arguments required to build validator overseer are provided"),
+		)?
+		.replace_runtime_api(move |ra_subsystem| {
+			InterceptedSubsystem::new(ra_subsystem, IgnoreDisabled)
+		})
+		.build_with_connector(connector)
+		.map_err(|e| e.into())
 	}
 }