implement CRUD on all logic layers

...src/main/java/cz/fi/muni/pa165/api/employee/Employee.java

.../fi/muni/pa165/api/employee/requests/EmployeeRequest.java

airports-hr-service/pom.xml

...-service/src/main/java/cz/fi/muni/pa165/hr/Constants.java

...rvice/src/main/java/cz/fi/muni/pa165/hr/dao/Employee.java

...-service/src/main/java/cz/fi/muni/pa165/hr/dao/Pilot.java

...ervice/src/main/java/cz/fi/muni/pa165/hr/dao/Steward.java

.../fi/muni/pa165/hr/excdption/EmployeeNtFoundException.java

.../main/java/cz/fi/muni/pa165/hr/facade/EmployeeFacade.java

.../java/cz/fi/muni/pa165/hr/repository/PilotRepository.java

...ava/cz/fi/muni/pa165/hr/repository/StewardRepository.java

...ain/java/cz/fi/muni/pa165/hr/rest/EmployeeController.java

...c/main/java/cz/fi/muni/pa165/hr/rest/PilotController.java

...main/java/cz/fi/muni/pa165/hr/rest/StewardController.java

...ain/java/cz/fi/muni/pa165/hr/service/EmployeeService.java