Resolve "Add teaser image per database for the frontend (e.g. university logo)"

.docs/.swagger/api-metadata.yaml

dbrepo-authentication-service/dbrepo-realm.json

dbrepo-metadata-db/setup-schema.sql

dbrepo-metadata-service/Dockerfile

...api/src/main/java/at/tuwien/api/database/DatabaseDto.java

...n/java/at/tuwien/api/database/DatabaseModifyImageDto.java

...s/src/main/java/at/tuwien/entities/database/Database.java

...repositories/src/main/java/at/tuwien/mapper/S3Mapper.java

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

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

...ice/rest-service/src/main/resources/application-local.yml

...a-service/rest-service/src/main/resources/application.yml

...ce/src/test/java/at/tuwien/annotations/MockListeners.java

...rest-service/src/test/java/at/tuwien/config/S3Config.java

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

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

...java/at/tuwien/service/StorageServiceIntegrationTest.java

...ce/rest-service/src/test/resources/application.properties

...ice/services/src/main/java/at/tuwien/config/S3Config.java

...ces/src/main/java/at/tuwien/listener/StorageListener.java