Add options to follow the Night Light state for turning on/off the Bedtime Mode

[ionutbortis]

Some people might want to have the Bedtime Mode enabled automatically when the Night Light is also turned on.

We should take here into consideration the fact that Night Light actually starts one hour earlier in order to accommodate the color change. Maybe we should also add some kind of delay option for Bedtime Mode. Another option would be to start the Bedtime Mode only when the Night Light temperature reached its configured peak.

One user suggested that it would be nice to also have a sunset-to-sunrise schedule option.