* Make light controllable independently with types V_LIGHT, V_DIMMER,
V_RGB and V_RGBW. V_RGBW is not implemented in the frontend yet.
* Add discovery for light platform.
* Add optimistic mode config setting for switch and light
to allow feedback state from actuator.
* Move S_LIGHT, V_LIGHT, V_STATUS types from switch to light platform.
* Change node update logging to debug from info level.
* Fix some inaccurate comments.
