feat: Add support for regex type questions #38 (#45)

backend/README.md

...ain/java/com/quiz/converter/handlers/FeedbackHandler.java

...ain/java/com/quiz/converter/handlers/QuestionHandler.java

...om/quiz/converter/handlers/QuestionValidationHandler.java

...va/com/quiz/converter/models/enums/QuestionErrorType.java

...in/java/com/quiz/converter/models/enums/QuestionType.java

.../com/quiz/converter/models/enums/QuestionWarningType.java

...m/quiz/converter/services/CourseraDocxCreatorService.java

.../com/quiz/converter/services/MoodleXmlCreatorService.java

backend/src/main/resources/static/singleChoice.docx

...ain/resources/static/single_choice_multiple_pictures.docx