* Actually connect to new validators at session boundary.

* Add tracing.

* validator_discovery: simplification

* compilation fixes

* compilation fixes II

* compilation fixes III

* compilation fixes IV

* 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>

* gossip: do not issue a connection request if we are not a validator

* guide updates

* use all relevant authorities when issuing a request

* use AuthorityDiscoveryApi instead

* update comments to the status quo

* gossip: choose random subset on send

* naming bikeshed

* add number to `ActivatedLeavesUpdate`

* update subsystem util and overseer

* use new ActivatedLeaf everywhere

* sort view

* sorted and limited view in network bridge

* use live block hash only if it's newer

* grumples

* Improve logging

* Review feedback

* Fix some warning and some further logging changes

* prefix parachain log targets with parachain::

* even more consistent

* initial subsystem for issuing connection requests

* finish the initial impl

* integrate with the overseer

* rename to gossip-support

* fix renamings leftover

* remove run_inner

* fix compilation

* random subset of sqrt