Merge branch 'refactoring' into 'main'

src/main/java/ch/jaermann/quiz/Helper.java

src/main/java/ch/jaermann/quiz/QuizApp.java

...main/java/ch/jaermann/quiz/controller/QuizController.java

src/main/java/ch/jaermann/quiz/creater/DocumentCreater.java

...java/ch/jaermann/quiz/creater/DocumentCreaterFactory.java

...ter/adoc/controller/MultipleChoiceQuestionController.java

...z/creater/adoc/controller/OpenTextQuestionController.java

...mann/quiz/creater/adoc/controller/QuestionController.java

...aermann/quiz/creater/adoc/controller/QuestionFactory.java

...eater/adoc/controller/SingleChoiceQuestionController.java

...creater/libreoffice/MultipleChoiceQuestionController.java

.../quiz/creater/libreoffice/OpenTextQuestionController.java

...jaermann/quiz/creater/libreoffice/QuestionController.java

...ch/jaermann/quiz/creater/libreoffice/QuestionFactory.java

...nn/quiz/creater/smartlearn/DocumentCreaterSmartLearn.java

...r/smartlearn/controller/MultipeChoiceQuestionBuilder.java

...n/quiz/creater/smartlearn/controller/QuestionBuilder.java

...creater/smartlearn/controller/QuestionBuilderFactory.java

...er/smartlearn/controller/SingleChoiceQuestionBuilder.java

...artlearn/controller/UnsupportedQuestionTypeException.java