Add LICENSE - AGPL

[Lkruitwagen]

Description

Please explain the changes you made here.

Checklist

• [ ] Dependencies install correctly in a clean environment and code executes;
• [ ] Test coverage extended; created tests fail without the change (if possible);
• [ ] All tests passing;
• [ ] Commits follow a type convention (e.g. https://gist.github.com/brianclements/841ea7bffdb01346392c#type);
• [ ] Extended the README, documentation and/or docstrings, if necessary;