Support RGBW Values as an Alternative to Hue and Saturation

[juangamnik]

My light bulb expects brightness and either red, green, blue, white or temp values (if in color or white mode respectively). You can add a gain value, too, but I'm not aware what it does...

So it would be great, if one could set the RGB-Values via http instead of hue and saturation. If Homebridge expects it this way, of course this would then needed to be converted. I can try to add this myself, but at a first glance at your code I could not see how to implement this.

Thank you very much in advance.