fix(dataObjects): Fix moving of data object refs

- if a diagram is a collaboration, then you are not able to move a data
  object references outside a pool
- furthermore, dependent of the scope of a data object it is not possible
  to move a data object reference outside the scope (for example from one
  pool to another pool)
- if data object will be removed, then all data object references, which
  have a reference to this data object, will be deleted to to be conform
  with BPMN 2.0 specification (see section 10.3.1, figure 10.51, page 205)

related to CAM-1379, CAM-1363
Merge branch 'master' of github.com:camunda/camunda-modeler