Collation protocol: stricter validators (#2810)

* guide: declare one para as a collator

* add ParaId to Declare messages and clean up

* fix build

* fix the testerinos

* begin adding keystore to collator-protocol

* remove request_x_ctx

* add core_for_group

* add bump_rotation

* add some more helpers to subsystem-util

* change signing_key API to take ref

* determine current and next para assignments

* disconnect collators who are not on current or next para

* add collator peer count metric

* notes for later

* some fixes

* add data & keystore to test state

* add a test utility for answering runtime API requests

* fix existing collator tests

* add new tests

* remove sc_keystore

* update cargo lock

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

polkadot/node/subsystem-util/src/validator_discovery.rs

@@ -46,7 +46,7 @@ pub async fn connect_to_validators<Context: SubsystemContext>(
 	validators: Vec<ValidatorId>,
 	peer_set: PeerSet,
 ) -> Result<ConnectionRequest, Error> {
-	let current_index = crate::request_session_index_for_child_ctx(relay_parent, ctx).await?.await??;
+	let current_index = crate::request_session_index_for_child(relay_parent, ctx.sender()).await.await??;
 	connect_to_validators_in_session(
 		ctx,
 		relay_parent,
@@ -64,11 +64,11 @@ pub async fn connect_to_validators_in_session<Context: SubsystemContext>(
 	peer_set: PeerSet,
 	session_index: SessionIndex,
 ) -> Result<ConnectionRequest, Error> {
-	let session_info = crate::request_session_info_ctx(
+	let session_info = crate::request_session_info(
 		relay_parent,
 		session_index,
-		ctx,
-	).await?.await??;
+		ctx.sender(),
+	).await.await??;
 
 	let (session_validators, discovery_keys) = match session_info {
 		Some(info) => (info.validators, info.discovery_keys),