Updated further metrics

.../src/main/java/at/tuwien/endpoints/ContainerEndpoint.java

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

...ice/src/main/java/at/tuwien/endpoints/ExportEndpoint.java

...src/main/java/at/tuwien/endpoints/IdentifierEndpoint.java

...vice/src/main/java/at/tuwien/endpoints/ImageEndpoint.java

...ce/src/main/java/at/tuwien/endpoints/LicenseEndpoint.java

...rc/main/java/at/tuwien/endpoints/MaintenanceEndpoint.java

...rc/test/java/at/tuwien/mvc/PrometheusEndpointMvcTest.java

...a-service/test/src/main/java/at/tuwien/test/BaseTest.java