add integration test for postgres service

docker-compose.yml

fda-table-service/pom.xml

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

...ce/rest-service/src/test/java/at/tuwien/BaseUnitTest.java

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

.../test/java/at/tuwien/service/PostgresIntegrationTest.java

...ice/src/test/java/at/tuwien/service/PostgresUnitTest.java

...services/src/main/java/at/tuwien/config/DockerConfig.java

...rvices/src/main/java/at/tuwien/service/JdbcConnector.java

...ices/src/main/java/at/tuwien/service/PostgresService.java

...ervices/src/main/java/at/tuwien/service/TableService.java