Adhere more to modern Python best practices

[Joseph-Edwards]

The Scientific Python Library Development Guide provides tools and guides on how write good scientific packages. From their website:

Topical guides provide task-based instruction on topics that scientists and research software engineers may encounter as their projects evolve and grow. This covers modern packaging (simple or compiled), style checking, testing, documentation, static typing, CI, and much more!

Having read through several of these, I think many of them would be easy for us to implement/adhere to. This issue serves as a way of tracking which (if any) of their suggestions we implements.

Things we could do:

• Use pyproject.toml comprehensively (Modernise the build system #237).
• Use pre-commit to check/enforce code style.
• Have a working CI job for making releases.
• Use MyPy for static type checking.
• Use ruff more aggressively for linting and formatting (Update linter and formatter config #354).