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/network/bridge/src/lib.rs

@@ -1794,6 +1794,7 @@ mod tests {
 			let collator_protocol_message = protocol_v1::CollatorProtocolMessage::Declare(
 				Sr25519Keyring::Alice.public().into(),
 				Default::default(),
+				Default::default(),
 			);
 
 			let message = protocol_v1::CollationProtocol::CollatorProtocol(
@@ -2064,6 +2065,7 @@ mod tests {
 				let collator_protocol_message = protocol_v1::CollatorProtocolMessage::Declare(
 					Sr25519Keyring::Alice.public().into(),
 					Default::default(),
+					Default::default(),
 				);
 
 				let message = protocol_v1::CollationProtocol::CollatorProtocol(