Remove logic to automatically send registration data to question options

[MartinBenediktBusch]

Note

PR can be reviewed but should be merged to develop only after v.2.5.0 https://github.com/lexicongovernance/pluraltools-backend/pull/322 has been merged to main. Furthermore, this PR should only be merged from develop to main once registration for existing proposals gets closed.

The PR itself removes the questionOptionType column which can be either Title, Subtitle, or Null from registration fields,including the functionality to pass this data to the question options table. However, I kept the questionId column in registrationFields to be able to to distinguish registrations by questionId.

Furthermore, I kept the registrationId and userId in the `questionOptions table to be able to uniquely identify a question option by user and registration. Furthermore, setting registrationId and userId equal to null retains the functionality to set custom question options that are defined by us.

Note: Removing this feature requires the admin to insert registration options to the question options table. This must be developed.

[MartinBenediktBusch]

Make PR consistent with new backend changes.