Refactor Button (spike)

Right now, buttons have custom props for colors (activeColor, hoverColor, mainColor).

We should try to simplify/standardize this into something that is more flexible for re-use.

Reconsider the architecture of props to make it more deliberate decision for 1.0 so we don't regret these props later.

Goal of this ticket would be to feel good about the button architecture and props.

Acceptance criteria:
- should have a branch with any proposed prop/api changes to Button
- should have documentation updates for any changes
- should change subcomponents to use a variant prop (`` should be ``)

E: 1D