* Eliminate extra accounts select query from FollowService

* Optimistically update follow state in web UI and hide loading bar

Fix #6205

* Asynchronize NotifyService in FollowService

And fix failing test

* Skip Webfinger resolve routine when called from FollowService if possible

If an account is ActivityPub, then webfinger re-resolving is not necessary
when called from FollowService. Improve options of ResolveAccountService

Offload creation of local notifications to a worker. Remove two
redundant SQL queries from ProcessMentionsService, remove n+1
XML/JSON serialization via memoization