refactoring RecipeSearch, slight visual changes, now selecting ingredients in recipe creator and validating number inputs

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

Deserialize methods in FileManager now take the JSON string as parameter. Fixed bug where empty files would cause NullPointerExceptions. All classes now work depend on an instance of TastyPages instead of static class members in TastyPages

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).

simplified NutritionTable equals() method. created component classes for RecipeTile and CategoryCheckBox

started moving dependencies to TastyPages class. Colour codes for categories are now saved in a string. recipe search by category works now, including UI updates

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

added BaseController that stores FXML files for all views, started bugfixing for equals methods, started working on recipe view fxml file

improved add-methods and knew method to check csv for other measurements than g and convert them to gram

Added parser to retrieve Ingredients from CSV files. includes tests. toString method for Ingredients. new NutritionTable constructor to create objects from List<Double>.

added more validation to Recipe constructor, fixing bugs in RecipeSearch, tests for RecipeSearch. now adding full recipes to the shopping list