Do a "0.1" release

[andreww]

This should:

• Automate running updates to main through pypi testing
• Automate new releases going to pypi itself
• Include some documentation on read the docs
• Get DOIs for releases.

[andreww]

• Move from requierments.txt to pyproject.toml, enable local pip install

[andreww]

All automated via github releases (doing a release creates stuff on PyPI). Done a 0.1.0a2 release. Sort out some documentation etc. ahead of 0.1