Buffered connection management for collator-protocol (#6022)

* Extract metrics into a separate module

* Introduce validators buffer

* Integrate buffer into the subsystem

* Only reconnect on new advertisements

* Test

* comma

* doc comment

* Make capacity buffer compile time non-zero

* Add doc comments

* nits

* remove derives

* review

* better naming

* check timeout

* Extract interval stream into lib

* Ensure collator disconnects after timeout

* spellcheck

* rename buf

* Remove double interval

* Add a log on timeout

* Cleanup buffer on timeout

polkadot/Cargo.lock

@@ -555,9 +555,9 @@ checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "bitvec"
-version = "1.0.0"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1489fcb93a5bb47da0462ca93ad252ad6af2145cce58d10d46a83931ba9f016b"
+checksum = "1bc2832c24239b0141d5674bb9174f9d68a8b5b3f2753311927c172ca46f7e9c"
 dependencies = [
  "funty",
  "radium",
@@ -6290,6 +6290,7 @@ version = "0.9.29"
 dependencies = [
  "always-assert",
  "assert_matches",
+ "bitvec",
  "env_logger 0.9.0",
  "fatality",
  "futures",