Retrieve and test the migration scripts.
Plan:
- [x] Test migration
- [x] Ask for help by email if needed
- [x] Report status in [1]
- [x] Follow up to Frank Duncan and Karl Fogel by email
- [ ] Waiting for feedback
[1] https://hedgedoc.softwareheritage.org/ezUtxkTDSJ-JBLARYrWIjA?view
Extra:
- [ ] What to do with local patches to make the migration work? Propose upstream?