Appy property merging rules

[StefanApfel-Bentley]

What to do:
When merging properties the following rules should be added to the current merging logic.

Tasks

Beta Give feedback

1. Allow changing the properties Kind-Of-Quantity if the persistence unit is the same
2. Allow changing the enumeration on primitive properties
3. Allow to merge int or string properties to enumeration properties if isStrict is set to false