Support for color widget

In UIP2, I would say the prop type is string

Sure about that? Why not a specific prop type?

What would be the JSON schema of this prop type?.

Discussed with @pdureau, moving to UI Patterns Settings because color in design system is driven by either style utilities or with CSS variables.

I propose to handle everything in ✨ Support for color widget Active .

grimreaper → closed merge request !39