Reworked the rollback

Makefile

...ien/exception/BrokerVirtualHostModificationException.java

...e/src/main/java/at/tuwien/endpoints/DatabaseEndpoint.java

...rvice/src/main/java/at/tuwien/endpoints/UserEndpoint.java

...src/main/java/at/tuwien/handlers/ApiExceptionHandler.java

...rc/test/java/at/tuwien/config/MariaDbContainerConfig.java

...st/java/at/tuwien/endpoints/DatabaseEndpointUnitTest.java

...c/test/java/at/tuwien/endpoints/UserEndpointUnitTest.java

...test/java/at/tuwien/gateway/BrokerServiceGatewayTest.java

.../tuwien/service/AuthenticationServiceIntegrationTest.java

...at/tuwien/service/MessageQueueServiceIntegrationTest.java

...t/java/at/tuwien/service/QueryServiceIntegrationTest.java

...st/java/at/tuwien/service/UserServiceIntegrationTest.java

.../src/test/java/at/tuwien/service/UserServiceUnitTest.java

...src/main/java/at/tuwien/gateway/BrokerServiceGateway.java

...ices/src/main/java/at/tuwien/gateway/KeycloakGateway.java

...java/at/tuwien/gateway/impl/BrokerServiceGatewayImpl.java

...main/java/at/tuwien/gateway/impl/KeycloakGatewayImpl.java

...rc/main/java/at/tuwien/service/AuthenticationService.java

.../src/main/java/at/tuwien/service/MessageQueueService.java