Investigate the usefulness of the nox project for dev scripts

[Kamforka]

nox is a command-line tool that automates testing in multiple Python environments, similar to tox. Unlike tox, Nox uses a standard Python file for configuration.

Maybe it's a better alternative to the custom scripts/ci.py and scripts/cd.py scripts.

Let's give it a try and if it works out the following need to be done:

• migrate the ci.py and cd.py scripts into noxfile.py
• change the commands in the affected github actions
• document the usage in the contributions section of the README
• enjoy life