Add ruff to the repo linters

[jacobtomlinson]

Folks seem to be excited about ruff as a fast replacement for flake8/isort/pyupgrade/etc.

Using it in the deployment docs for linting the example scripts and Sphinx extensions felt like a low-effort/low-risk place to try it out.

I've added it to the pre-commit config so it will get run on commit and in CI. You can optionally install it yourself with pip install ruff and run it on files with ruff path/to/file.py.