This PR adds the ability to export tokens for each theme. 

You can export tokens by:

1. `cd styles`
2. `npm run build-tokens`
3. Tokens will be output in the target folder (`styles/target`)

The tokens match the ColorScheme object. In the future we may also
export tokens for our styleTrees.

Release Notes:

- N/A (No public facing changes)

---
TODO:

- [x] Generate Token Studio theme index file
- [x] ColorScheme
    - [x] name:
    - [x] isLight
    - [x] lowest
    - [x] middle
    - [x] highest
    - [x] popoverShadow
    - [x] modalShadow
    - [x] players
    - [x] syntax