Implement custom color picker (from PlugData)

[sudara]

Timothy from PlugData has graciously offered we steal their custom color picker so we can move away from JUCE's default one.

https://github.com/plugdata-team/plugdata/blob/main/Source/Utility/ColourPicker.h

[reFX-Mike]

We have a more fully featured one here:

https://github.com/reFX/ColourSelector

It's the same functionality as Photoshop. The means the color-space square changes according to the mode, etc.

We could work together to make it prettier. It's based on the JUCE one, but then added features:

[sudara]

Hey nice work!

For the inspector I'd like to:

• Be able to pass in a hex/rgba preference for output value. Many of us working in vector/web are often more used to working with r,g,b,a values instead of hex
• Have an alpha slider
• Hide the "picked color" (the selector is pointing to it and it's visible in context)
• Hide all the HSB/RGB values and sliders

So basically, I'd like to end up with similar to the PlugData version here (though the toggle isn't necessary since there's a toggle in the inspector already).

[reFX-Mike]

Except for the output as RGB values instead of hex, this is all supported. It uses the usual "flags" in the constructor and you can turn everything on/off invidivually.

[sudara]

Nice!

For the inspector, I've also been thinking that the color picker should enable when the selector pops open (like every other app's color selector) and allow for repeated picking...

[reFX-Mike]

100% agree