Convert adafruit_bus_device, adafruit_pixelbuf, analogio, atexit, audiobusio, audiocore, audioio, audiomixer, and audiomp3 modules to use MP_REGISTER_MODULE.
Related to #5183.
This was done to allow greatly granularity when deciding what functionality
is built into each board's build. For example, this way pulseio can be
omitted to allow for something else such as touchio.