Dependencies between edit_weekplan_bloc and weekplan_selector_bloc

[FrederikBendix]

There is a method in weekplan_selector_bloc, which are currently only being used by other BLoCs (edit_weekplan_bloc). This method is deleteWeekModel

Consider whether this is good case practice, and whether it could be implemented in a smarter way

Note: This issue is regarding BLoC design pattern and refactoring the BLoCs. Consider assigning proper amount of time to solve this issue, as it requires a good understanding of the design pattern!