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.

As requested by moon2. Spikes is the default as that's what p4 uses and
the current code handles decently, spirals is new in p6 and ideally
should have its own implementations for rad and phi, right now it has
placeholders.

It was never actually supported by the codebase (the port expanders are
completely different and only implemented in the other repo)

Yeah I'm aware all of this can change any time, yell at me if it's a
problem.

Previously MicroPython would mount LittleFS directly from the partition
by itself, using its own VFS stack.

This reconfigured the VFS layer in MicroPython to use POSIX
open/read/write/etc calls, which are backed by ESP-IDF. Now, instead of
managing (possibly multuple) block devices at different mountpoints,
MicroPython simply passes through all VFS access to the ESP-IDF VFS.

Then, we make the ESP-IDF VFS mount a wear-leveled FAT (backed by the
same partition which previously held LittleFS) onto /.