[Scenario] Add info about drag-drop to policy

When considering availability of drag-drop
actions via policy, provide key/value hints
about which action is being employed. This
permits external plug-ins to modify their
behavior in special cases where normal
Move/Copy/Link rules are insufficiently
descriptive.

This is needed for the scenario distribution,
where Move (and not Link) should be
available when dragging Activity Type
objects between repositories.
[Platform] Update drag-drop action names
[Platform] Reorder Move/Copy/Link options
[Platform] Repair grammar of drag-drop dialog
Merge pull request #260 from VWoeltjen/mct179followup

[Platform] Follow-up on Move/Copy/Link