Unified Color Picker Tools for Lights/Objects

The proposal is to make light objects and color-picker objects have identical color-picking UI and utility.

Current object color pickers offers a color slider, which is too bright. If it had a black-to-white brightness slider, it would provide more utility.

Current light color picker offers 10 static colors and a black-to-white brightness slider.

(I recognize that certain objects also have shader pickers, which are understandably different animals, and not really considered within this proposal. E.G. the force shield.