Draft: main/postmarketos-base-ui: use font presets

Depends on https://gitlab.com/postmarketOS/pmaports/-/merge_requests/5540

Fixes https://gitlab.com/postmarketOS/pmaports/-/issues/2069

Breaking change: the UI font is Droid by default now, for image size and language coverage! Feedback if disagree!

Open questions:

• DejaVu is no longer installed unconditionally, so packages depending on DejaVu must depends on font-dejavu explicitly, like main/fbkeyboard. Is it okay?
  • Is DejaVu a hard dependency for fbkeyboard by the way?