Extend Style Options in Customizer

[vlaisavljevic]

Describe the feature:
There is a suggestion for improving the Site Design option in the customizer, i.e adding additional options for text colours.
https://wordpress.org/support/topic/design-style-modern-color-bug/#post-15394883

[jrtashjian]

Closing this issue as we focus on the Full Site Editing work currently underway in Go.

We will no longer be supporting the customizer as site editor replaces it.