Enhance collaboration

[patnr]

Off the top of my head, the following should be fairly quick to address,
and the gain in "rigour" should encourage improved professionalism.

• Sanity checks, ref Create sanity checks #41
• Developer guidelines (?), ref Generate guidelines for contributions #10. See docs/dev_guide.md
• e3c26dd broke the docs. I will see if we can work-around not having the __init__
• Add linting to minimize diff noise? I suggest ruff, which also comes with formatter.
• Add some kind of CHANGELOG, preferably created by CI + manual review (somehow).
• Improve installation instructions.