Added color palette feature for Wrapper

[fers4t]

I think this feature might be useful if users want to use their own color palette.

[nusu]

That's a bit problematic...
So if we are going that way, both Background and Foreground colors should be editable.
Also, the length of Foreground colors and Background colors should be equal otherwise plugin has to throw an error.

Enabling this, will dramatically reduce the chance of creating unique combinations, yet people might want to edit colors to their brand colors, that's totally understandable.

Thank you for your contributions, I'm going to think about that.

[fers4t]

This is right.
We can use tinycolor2 to play with colors and give avatars a good look.
But I don't know if it's worth ✌🏻