This is replaced by more mpy-centric code for user interaction plus
bl00mbox for the actual sound framework.

We already moved LEDs to their own task. Let's try doing that for
jacksense too. As long as we don't run out of RAM this should be better
than having larger tasks, as things won't block eachother that much..?

1. Add locking (st3m_audio_* functions are now thread/task-safe).
2. Remove some duplicate code around speaker/headphones output.
3. Simplify applying audio volume to codec ('apply' function).
4. Small style stuff (bool, etc).

This moves all I2C addresses and locking logic into the BSP.

Removes sdkconfig.p* files, use a single sdkconfig.defaults.

This is now 'overlaid' with flow3r-specific options by idf_ext.py.

This seem to break mpremote mount, and I'm not sure why we even want
them.

Renames font constants so they match the indexing used by
ctx_get_font_name.