Add freinet client id to region settings

[ztefanie]

For this feature #1751
We need an API from freinet and our users need to input a freinet-client-id inside their region settings to ensure the mapping of our region to the fitting freinet-region. For exmaple the transfer to freinet could/should not be possible if the freinet-client-id is not maintained.

• Fetch the freinet client id in regular cycles and the maybe (or not) save them to our system. Evaluate if caching is enough or not. Updates in the freinet system are possible and need to lead to updates in our system, e.g. if a region is added to freinet.
• Add a freinet-client-id input field to the region settings
• Validate that only freinet-client-ids can be added to the region settings that are valid.

[f1sh1918]

Maybe I overseen sth but why do we have to create an input field for the Client id @ztefanie ? We fetch the regions including a region identifier (not available yet), access Key, mandantenId(freinet) with that we can map the Region to our RegionId and have All required information to push the card and user data.
I thought we keep this information in memory.
@ztefanie