Add CONTRIBUTING.md

[simonhammes]

Closes #278
Fixes #475

[jrfnl]

Hi @simonhammes Thanks for getting this updated! Much appreciated.

Even though the PR is still marked as draft, I though I'd give you some feedback already. Hope it helps! Please let me know if you have any questions.

Aside from the inline remarks:

README

The README contains some information at the bottom about Testing and Contributing.

I think it would be a good idea to remove that information and replace it with a link to this CONTRIBUTING document.

I'd also like to suggest checking if there is anything mentioned in the information at the bottom of the README which isn't covered by the currently proposed CONTRIBUTING document and if so, to update the CONTRIBUTING doc.

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Please note: while in the line remarks I have used inline links, it is good practice to move the links to the end of each section in a markdown document (but the "suggest" feature for PR reviews doesn't really play nice with that).

[jrfnl]

@simonhammes Just so you know, we think you are doing a great, momentous job with your work on this PR. Please see our feedback as encouragement.

Will you have time to update the PR in the near future ? I'd love to get this ready & merged!

If not, please let us know and we'll be happy to sort out the next iteration.

[jrfnl]

@simonhammes Just so you know, we think you are doing a great, momentous job with your work on this PR. Please see our feedback as encouragement.

Will you have time to update the PR in the near future ? I'd love to get this ready & merged!

If not, please let us know and we'll be happy to sort out the next iteration.

@simonhammes 👆🏻 Could you please let us know if you will continue with this PR or want us to take over ?

[jrfnl]

This PR has been superseded by an updated version in #762, which has now been merged. Thanks @simonhammes for helping us get this over the finish line.