This is another take on #1026 that aims to minimally implement a Nix development environment.
Notable differences are:
- Uses `pyproject.nix` for auto-packaging of the environment
- Mach-nix is unmaintained
Not only is it unmaintained but extremely heavy weight.
- Uses nixpkgs Python packages
Which means better binary cache performance than mach-nix offers.
- No direnv additions
I use direnv myself but expect users to be able to `echo 'use flake' > .envrc` if they want to use direnv.
- Uses zephyr sources from a flake input
This should make maintenance simpler as there is no manual updating required.
