This is a request we received from one of our pilot wikis - they would like to be able to have Automoderator send talk page messages to registered users, but not send them to unregistered users.
Acceptance Criteria
- Create community configuration boolean field for "Don't send talk page messages to anonymous/temp users" (wording TBD)
- add guard clause to early return if true before sending talk page message
- maintain current behavior by default
- add variable to documentation at https://www.mediawiki.org/wiki/Extension:AutoModerator
