The stub seems to break uploading from running firmware on newer
ESP-IDFs.

There's a better way to fix this by patching esptool.py, but this is
good enough for now.

https://www.esp32.com/viewtopic.php?t=10184#p42176

Contributor sign-offs: https://git.card10.badge.events.ccc.de/badge23/firmware/-/issues/5

This is an annoyingly large change, but the gist of it is that we:

1. Move ctx into components/ctx
2. Move uctx into usermodule/mp_uctx.c
3. Split out uctx config into ctx_config.h and share it with the
   simulator.
4. Delete a bunch of unused ctx files
5. Flip some ctx bits for speed.
6. Draw the rest of the owl, ie. implement a dedicated rasterizer task
   in components/st3m.