I don't know why, but micropython has files that absolutely break my git
experience, leading to 'phantom' dirty files that I can't seem to clean
up.

Feel free to revert this if this messes something up.

This adds initial support for building on Nix(OS). It can be tested by
following the updated README.md. The result should be the ability to
build the firmware without having to download any other dependencies.

This is the initial commit of the flow3r firmware repository. You will
notice that it's at a later date than subsequent commits - that's
because it's the effect of a history rewrite.

The initial firmware repository started as an experimental Micropython
git fork. After a while we've decided that keeping the entirety of the
Micropython history in-repository was a bad idea, so we rewrote history.