OZG-7350 implement zustaendigeStelle as Fachstelle

collaboration-manager-server/pom.xml

...loud/collaboration/CollaborationManagerConfiguration.java

.../java/de/ozgcloud/collaboration/CollaborationRequest.java

...de/ozgcloud/collaboration/CollaborationRequestMapper.java

.../java/de/ozgcloud/collaboration/CollaborationService.java

...java/de/ozgcloud/collaboration/fachstelle/Fachstelle.java

...e/ozgcloud/collaboration/fachstelle/FachstelleMapper.java

...oud/collaboration/fachstelle/FachstelleRemoteService.java

.../ozgcloud/collaboration/fachstelle/FachstelleService.java

...zgcloud/collaboration/CollaborationRequestMapperTest.java

...gcloud/collaboration/CollaborationRequestTestFactory.java

...de/ozgcloud/collaboration/CollaborationServiceITCase.java

...a/de/ozgcloud/collaboration/CollaborationServiceTest.java

...gcloud/collaboration/fachstelle/FachstelleMapperTest.java

...collaboration/fachstelle/FachstelleRemoteServiceTest.java

...cloud/collaboration/fachstelle/FachstelleServiceTest.java

...cloud/collaboration/fachstelle/FachstelleTestFactory.java

...ud/collaboration/fachstelle/GrpcAnschriftTestFactory.java

...ation/fachstelle/GrpcFachstelleGetRequestTestFactory.java

...tion/fachstelle/GrpcFachstelleGetResponseTestFactory.java