* Cleanup async_track_state_change and augment docstrings.

Skip from_state and to_state matching in
async_track_state_change when they are None

Optimize the state change listener for the most
common use case: no to_state and from_state
matching.

* Update benchmark to be more realistic (previously we assumed only one entity was present in the whole instance)

* Add more tests to ensure behavior is preserved

* Ensure new behavior matches test

* remove MATCH_ALL from zone automation since its the default anyways

* Might as well use async_track_state_change_event instead since MATCH_ALL is removed