Convert services to TypeScript, part 1

[pugnascotia]

Summary

This PR converts roughly half the services to TypeScript. Implementation notes:

• In browser.ts, I tried to make it clear what contract Browser was fulfilling, and I may have ended up with something more verbose that necessary.
• color_palette.ts had its own hex -> RGB convertor, so I replaced it with hexToRgb. I also removed formatHex() since it was redundant.
• In rgb_to_hex.ts, I replaced the single ugly regex with two passes to simplify the implementation. I could still do it in one, and maybe it would be more legible than before? Opinions welcome. I also made it stricter, since the original didn't check the whole argument value i.e, you could pass rgb(1,2,3 and it would return a hex code.
• In random.ts, I ran up against Wrong 'this' context in class methods microsoft/TypeScript#3927 and had to make all the method definitions bound.

Checklist

• This was checked in mobile
• This was checked in IE11
• This was checked in dark mode
• Any props added have proper autodocs
• Documentation examples were added
• A changelog entry exists and is marked appropriately
• This was checked for breaking changes and labeled appropriately
• Jest tests were updated or added to match the most common scenarios
• This was checked against keyboard-only and screenreader scenarios
• This required updates to Framer X components

[pugnascotia]

I've added the tests that I intended, so this is no longer WIP.

[chandlerprall]

Couple small things & questions. Looks fantastic though.

[pugnascotia]

@chandlerprall I've addressed your feedback and rebased on master.

[chandlerprall]

LGreatTM !