Migrate to hatch/pyproject.toml

[Gadgetoid]

Should roughly use the setup provided here: https://github.com/pimoroni/boilerplate-python

This includes some changes to how linting/tests are handled and some other "improvements" that would be nice here.

[Gadgetoid]

I, uh, should probably get around to this sometime.

Since this is also a systemy tool we should look into things like uv, since uv run 32blit Just Works (I think).