Make mypy run with proper type stubs for micropython RP2.
Add basic structure for pytest testing.
Signed-off-by: Matthias Blankertz <matthias@blankertz.org>
The python and C modules that are supposed to be built into the firmware
image (i.e. those that are in manifest.py or in USER_C_MODULES) have
been moved to the software/modules directory.
The software/src directory should now only contain python scripts and
other files that should be installed to the Picos flash filesystem. The
idea is that these should be those scripts that implement the
application behaviour, as these are the ones that a user who does not
want to build the whole firmware themself wants to modify.
