Merge branch 'develop' into 'check-style'

# Conflicts:
#   domain-module/src/main/java/cz/muni/fi/pa165/airportmanager/domainmodule/service/RetrieveEntityServiceImpl.java
#   domain-module/src/main/java/cz/muni/fi/pa165/airportmanager/domainmodule/service/RetrieveMultipleEntitiesByIdServiceImpl.java
#   domain-module/src/main/java/cz/muni/fi/pa165/airportmanager/domainmodule/service/RetrieveMultipleEntitiesService.java
#   flight-module/src/main/java/cz/muni/fi/pa165/airportmanager/flightmodule/facade/FlightFacade.java
#   flight-module/src/main/java/cz/muni/fi/pa165/airportmanager/flightmodule/facade/FlightFacadeImpl.java
#   flight-module/src/main/java/cz/muni/fi/pa165/airportmanager/flightmodule/rest/FlightController.java
#   plane-module/src/main/java/cz/muni/fi/pa165/airportmanager/planemodule/facade/PlaneFacade.java
#   plane-module/src/main/java/cz/muni/fi/pa165/airportmanager/planemodule/facade/PlaneFacadeImpl.java
#   plane-module/src/main/java/cz/muni/fi/pa165/airportmanager/planemodule/rest/PlaneController.java
#   plane-module/src/main/java/cz/muni/fi/pa165/airportmanager/planemodule/service/FlightServiceImpl.java
#   plane-module/src/test/java/cz/muni/fi/pa165/airportmanager/planemodule/facade/PlaneFacadeImplTest.java
#   plane-module/src/test/java/cz/muni/fi/pa165/airportmanager/planemodule/rest/PlaneControllerTest.java
#   steward-module/src/main/java/cz/muni/fi/pa165/airportmanager/stewardmodule/facade/StewardFacadeImpl.java
#   steward-module/src/main/java/cz/muni/fi/pa165/airportmanager/stewardmodule/rest/StewardController.java
#   steward-module/src/main/java/cz/muni/fi/pa165/airportmanager/stewardmodule/service/AirlineServiceImpl.java
#   steward-module/src/main/java/cz/muni/fi/pa165/airportmanager/stewardmodule/service/DestinationServiceImpl.java
#   steward-module/src/test/java/cz/muni/fi/pa165/airportmanager/stewardmodule/endtoendtests/StewardEndToEndTests.java
#   steward-module/src/test/java/cz/muni/fi/pa165/airportmanager/stewardmodule/facade/StewardFacadeTest.java
#   steward-module/src/test/java/cz/muni/fi/pa165/airportmanager/stewardmodule/integrationtests/StewardIntegrationTest.java
#   steward-module/src/test/java/cz/muni/fi/pa165/airportmanager/stewardmodule/service/StewardServiceTest.java