Allow the definition of multiple PatientRetriever configurations and make them assignable for each clinic

[ywarnecke]

This way, we can decide where the information for a clinic should be fetched from. Multiple configurations should be possible both for the pseudonymization service and the patient data retriever.

Then for a clinic, a specific patient retriever, a specific pseudonymization service or the plain case number service can be activated. Depending on what was activated for a clinic, said options should be shown in the frontend for a user for the clinic.

[hussainsabir52]

Major updated:

• Model Addition:

1. Clinic Configuration
2. Clinic Configuration Mapping
3. Clinic Configuration Group Mapping

Functionalities:

• Patient retriever configurations are now only configurable clinic specific on the clinic edit page (Previously in global configuration), for that reason, all users must now be assign to at least one clinic and a clinic must have at least one patient retriever configured.
• Server information, must be added into the global configuration for patient retrievers that needs to be configured in the clinic.

[ywarnecke]

Merged with #102