[#95] Fixing button outline border bug

[nathan-schmidt-viget]

Summary

This fixes a few bugs with the button.

• Option to change the bg color and text color.
• The outline variant defaults to a transparent bg.
• When you set the text color it should set the border color.

Issues

• [Bug] Button outline style - border color #95

Testing Instructions

1. Add a block that has a button or just add the button block.
2. Make sure you can change the bg/text color.
3. The Outline variant defaults to a transparent bg.
4. When you set the text color for the outline variant it sets the border color.

Screenshots

Can set a bg/text color overriding the default for both variants.

When you set the text color it should set the border color.

[bd-viget]

LGTM! Thanks for updating this!