fbd-dev-led: Move multicolor handling to separate class

Everything related to multicolor moves into the new class and we add the
necessary getters and setters so derived classes can access the parent
classes attributes where needed.

src/meson.build

@@ -16,6 +16,7 @@ sources = [
   'fbd-dev-vibra.c',
   'fbd-dev-sound.c',
   'fbd-dev-led.c',
+  'fbd-dev-led-multicolor.c',
   'fbd-dev-leds.c',
   'fbd-event.c',
   'fbd-feedback-base.c',