Merge players with multiple protocols together (#3150)

* Base implementation of merging players through protocol linking

* Restore after merge conflict

* follow-up

* Fix config handling for players

* some tweaks

* Handle more (edge) cases

* bunch of fixes

* More fixes

* Some more tweaks

* Fix group_members calc

* A bunch of tweaks and refactoring

* more tweaks

* more follow-up

* Update controller.py

* refactoring groups

* more fixes for syncgroup

* fix readme nitpick

* revert frozen in uv run

* Add default providers conf

* fix tests

* more tweaks

* fixes for syncgroups

* More small tweaks

* more sync player tweaks