Purge Tailwind for base-2021

[madc]

I just started building a bolt theme using tailwind and invested some research in purging/minimizing the css. I described the current state here: bolt/project#51 (comment)

The tailwind setup should be part of the 2021 theme as it is a starting point for many developers. Let me know if that makes sense, I'd be willing to prepare a PR once my setup is "finished" and better tested.

[bobdenotter]

@madc Yes, that'd be most appreciated! 👍