New linting and Python builder

My goals here were to

1. simplify the build specification processing into a single pyproject.toml using hatch (rather than setuptools).
2. Simplify (and improve) formatting + linting using ruff as the one tool to rule them all.

I've also added support for pre-commit to keep us devs inline with liner rules, plus I've added

spinifex[dev,docs,test]

to the dependency options.