Badge => TypeScript

[mdespuits]

EXAMPLE. DO NOT MERGE YET.

This is an example of converting a JS component to TS. Step I took

1. Move index.js to Badge.tsx and create index.ts to re-export from the new Badge TS file.
2. Run tests.
3. Fix any immediate TS errors
4. Commit
5. Use React.FC and setup correct Badge props and resolve conflicts with PropTypes auto-typing.

I only made two small additions:

• Deprecate round to prefer isRound. Open to reverting this.
• Add typing to possible variants for useful autocomplete when using with consuming apps.

Fixes #182.