py: grand st3m unification

Commandeering @iggy 's stemming_merge branch and continuing his work.

This is now at the point where we fully moved st4m back into st3m, and we have the ability to launch applications from the new 'sun' menu.

I had to undo some changes that I hope to restore soon:

1. Captouch-based scroll. It still lives in comments.
2. The old flower-menu but rebuilt on top of the new menu/scroll framework.

But this at least brings us one step closer to production code, and unblocks a bunch of other stuff.

mentioned in merge request !30 (closed)

added 35 commits

• 125c9d65...302fc13c - 13 commits from branch main
• 302fc13c...148aa1db - 12 earlier commits
• 8a07a596 - py: st4m: fix wrap GestureScrollController
• af0baaab - mypystubs: add some missing undocumented stubs
• 05dcf315 - py: now passes typechecks
• 67c8932d - ci: mypy check main.py
• c2bbce44 - sim: add missing audio fake
• b6e0f537 - py: pull in st3m.logging into st4m
• fee84e6e - py: move st3m.system to st4m.sytem
• 3bd77c9e - py: remove st3m
• ddca99c4 - py: st4m -> st3m
• 7c98b0c6 - py: remove dead code

Compare with previous version

merged