Add questionnaires + implement POST methods, choices are not working yet though

README.md

...controller/AdaptiveTrainingDefinitionsRestController.java

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

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

...main/java/com/example/demo/domain/QuestionnaireLevel.java

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

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

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

...main/java/com/example/demo/dto/QuestionnaireLevelDto.java

...a/com/example/demo/dto/input/GameDefinitionCreateDto.java

src/main/java/com/example/demo/enums/LevelType.java

src/main/java/com/example/demo/enums/QuestionType.java

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

...com/example/demo/repository/QuestionChoiceRepository.java

.../java/com/example/demo/repository/QuestionRepository.java

...example/demo/repository/QuestionnaireLevelRepository.java

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

.../java/com/example/demo/service/QuestionChoiceService.java

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

...a/com/example/demo/service/QuestionnaireLevelService.java