Convert the schema to use a data property to store the serialized settings instead of having one property for each setting

Currently the entire schema is full of single value properties (settings) which could actually all be moved into one serialized data property. Is there a reason why every setting currently has its own column? Using a data property for the settings makes a lot of sense if you ask me and it is also way more flexible and could be used by other implementing modules to store additional information to customize specific quizzes, etc.