* Fix scheduled update time-drift in data update coordinator
As next schedule is calculated **after** the update is done,
setting now + update_interval makes 1 second drift in practice,
as the tick is 1Hz.
* Floor the utcnow timestamp
to remove sub-second error precision, and generate constant frequency updates
as long as the update takes < 1s.
* Refactor Hue Lights to use DataCoordinator
* Redo how Hue updates data
* Address comments
* Inherit from Entity and remove pylint disable
* Add tests for debounce
