Add a Code of Conduct #42
Description
This becomes relevant we we start having external contributions, but might also be expected as a prerequisite for contributions. So, let's not delay this too much.
Starting points:
- Code of Conduct section in CONTRIBUTING.md
- https://opensource.guide/code-of-conduct/
- https://dev.to/gomathia/code-of-conduct-toolkit-for-open-source-communities-5hdj
- https://book.the-turing-way.org/community-handbook/coc