Color Picker should use selected color

[beasteers]

Color Picker should check the selected text and if it's a color, then pass it to TouchBarColorPicker as selectedColor. Between color-string and color-convert, we should be able to read in the color, whether it be rgb, hsl, hex, etc. and convert it to hex to pass in. Also, it would be nice if we could convert back to the original format.