Added paste on gridcollection, case collection and cases

Moved creation of objects into rimUiTreeModelPdm
p4#: 20968

ApplicationCode/ProjectDataModel/RimCaseCollection.h

@@ -41,6 +41,8 @@ public:
 
     caf::PdmPointersField<RimReservoir*> reservoirs;
 
+    RimIdenticalGridCaseGroup* parentCaseGroup();
+
 private:
 
 };