Resolve "Allow subset creation without login"

.docs/api/ui.md

dbrepo-auth-service/dbrepo-realm.json

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

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

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

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

...src/main/java/at/tuwien/validation/EndpointValidator.java

...service/src/test/java/at/tuwien/config/MariaDbConfig.java

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

.../test/java/at/tuwien/endpoint/AccessEndpointUnitTest.java

...est/java/at/tuwien/endpoint/DatabaseEndpointUnitTest.java

.../test/java/at/tuwien/endpoint/SubsetEndpointUnitTest.java

...c/test/java/at/tuwien/endpoint/TableEndpointUnitTest.java

...rc/test/java/at/tuwien/endpoint/ViewEndpointUnitTest.java

...test/java/at/tuwien/handlers/ApiExceptionHandlerTest.java

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

.../java/at/tuwien/service/SubsetServiceIntegrationTest.java

...t/java/at/tuwien/service/TableServiceIntegrationTest.java

...rest-service/src/test/java/at/tuwien/utils/FileUtils.java

...t-service/src/test/java/at/tuwien/utils/UserUtilTest.java