[Cleanup] Rename PhaseLevel to TrainingPhase, corresponding changes

...in/java/com/example/demo/controller/PhasesController.java

src/main/java/com/example/demo/domain/BaseLevel.java

src/main/java/com/example/demo/domain/DecisionMatrixRow.java

src/main/java/com/example/demo/domain/Task.java

src/main/java/com/example/demo/domain/TrainingPhase.java

src/main/java/com/example/demo/dto/TrainingPhaseDto.java

...ain/java/com/example/demo/dto/TrainingPhaseUpdateDto.java

...ain/java/com/example/demo/facade/TrainingPhaseFacade.java

src/main/java/com/example/demo/mapper/BeanMapper.java

...main/java/com/example/demo/repository/TaskRepository.java

.../com/example/demo/repository/TrainingPhaseRepository.java

...java/com/example/demo/service/LevelOperationsService.java

src/main/java/com/example/demo/service/PhaseService.java

src/main/java/com/example/demo/service/TaskService.java

...n/java/com/example/demo/service/TrainingPhaseService.java