Add `ee285.test()` method

In order to more easily test code, we are adding in the ee285.test() method which can be used as a hook to call code that we write at the C level.

In order to test, first build circuit python, then flash the build to the feather board, then run in the REPL

import ee285
ee285.test()

You should then get this output:

This is the ee285 test function. 
 Edit  me in `software/firmware/circuitpython-main/shared-module/ee285/__init__.c`