OZG-7573 add poc version for EingangStubReceiverStreamObserver

forwarder/pom.xml

.../eingang/forwarder/EingangStubReceiverStreamObserver.java

...e/ozgcloud/eingang/forwarder/IncomingFileGroupMapper.java

...ava/de/ozgcloud/eingang/forwarder/IncomingFileMapper.java

...ain/java/de/ozgcloud/eingang/forwarder/RouteCriteria.java

...zgcloud/eingang/forwarder/RouteForwardingGrpcService.java

.../de/ozgcloud/eingang/forwarder/RouteForwardingMapper.java

...gang/forwarder/GrpcRouteForwardingRequestTestFactory.java

.../ozgcloud/eingang/forwarder/RouteCriteriaTestFactory.java

...oud/eingang/forwarder/RouteForwardingGrpcServiceTest.java

pom.xml

router/pom.xml