[FEATURE] Add a "contribute" paragraph to the readme

[Hechamon]

Is your feature request related to a problem? Please describe.
I'm wondering if you're open to pull requests, or if we should just create issues.

Describe the solution you'd like
Add a paragraph to the readme or a separate contribute.md or something where you write how you would like the community to interact.
Possible ways I would see are

• no contribution, just create issues
• create issue that you prioritize and label as "help wanted" or similar
• create issue and all of them are up for grabs
• fork and create pull requests freely
• other options? 🤷