Exploration: Use SuperSets to pass model data to the backend.

* Modify (Super)Sets to use a generic that denotes the types of elements within a set. Thereby, it is ensured that only elements of this kind are contained/referenced in a specific set.
* Introduce a SuperSetMap that allows to associate the types of elements of supersets with superset instances.
* Use the SuperSetMap as the main entity to pass model elements from the DSE Project to backends.
* Add the ComponentToTaskAllocationTable to the DSESuperSet and the DSE model element: This is the new way to identify which Tasks belong to which Component.
refs 2939