Short description

Currently we accept creating cards from csv even if some mandatory extensions are not included in the csv (like startDay or cardType)

Proposed changes

• add a check during the csv import if the initialized card has all mandatory extensions included and show an error message if sth is missing
• adjust the unit tests that were quite flaky
• add a unit test for the csv freinet import
• add a mandatory flag to each extension

Note: In the future it may make sense to set the mandatory flags not on the extension directly but in the cardConfig for each project. So far i don't see the use case. Just to keep that in mind that we may refactor our extension config in the project config if its getting more complex

Side effects

• csv import may break for the particular project

Testing

1. Test the csv import for nuernberg and for bayern (normal & freinet)
2. Check if csv data without the mandatory extensions can't be processed
   Bayern: Kartentyp
   NBG: Startdatum, Geburtsdatum, Pass-ID

Resolved issues

Fixes: #1868