flights id as UUID

...e/src/main/java/cz/muni/fi/pa165/facade/FlightFacade.java

...java/cz/muni/fi/pa165/facade/FlightRealizationFacade.java

.../main/java/cz/muni/fi/pa165/facade/IssueReportFacade.java

...muni/fi/pa165/repository/FlightRealizationRepository.java

...in/java/cz/muni/fi/pa165/repository/FlightRepository.java

...va/cz/muni/fi/pa165/repository/IssueReportRepository.java

...src/main/java/cz/muni/fi/pa165/rest/FlightController.java

...va/cz/muni/fi/pa165/rest/FlightRealizationController.java

...ain/java/cz/muni/fi/pa165/rest/IssueReportController.java

...va/cz/muni/fi/pa165/service/FlightRealizationService.java

...src/main/java/cz/muni/fi/pa165/service/FlightService.java

...ain/java/cz/muni/fi/pa165/service/IssueReportService.java

...test/java/cz/muni/fi/pa165/rest/FlightControllerTest.java

...test/java/cz/muni/fi/pa165/service/FlightServiceTest.java

...c/test/java/cz/muni/fi/pa165/service/IssueReportTest.java

...java/cz/muni/fi/pa165/hr/service/EmployeeServiceTest.java