Split GUI and the model into two classes. File manager is now fully implemented. the branch will be merged with main

Categories, recipes and ingredients now saved in hashmap together with their associated code and a whole bunch of refactoring to go along with it. TypeAdapters for Recipes, NutritionTables and Categories. Saving and retrieving Recipe, NutritionTable and Category to / from JSON works (see tests).

abstract class BaseController, figuring out dependency injection into JavaFX controllers, added enum View.java to get correct Scene object (with correct constructor)

changed Categories to CategoryManager and added IngredientManager with respective methods (partly moved from RecipeManager to IngredientManager)

boilerplate