Add async_track_state_added_domain for tracking when states are added to a domain

[bdraco]

Part 2 of reviving PR #23590

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[bdraco]

After writing this out, it might be able to go with async_track_state_added_domain directly and use the existing underlying EVENT_STATE_CHANGED like async_track_state_change_event

This would negate the need to add a new event. Seems cleaner if the work here #23590 (comment) only needs to know about new entities in specific domains