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

Follows up on nasa/mct#259

* Changes name of options presented after drag and drop (to "Move", "Copy", and "Copy Linked")
* Provides policy information necessary for Scenario plug-in to adjust behavior when dragging-dropping components between repositories (previously, a sepcial-case Move option had been implemented there; now)

```
 Wrote or re-wrote unit tests (Y/N): Y*
 Ran entire suite of unit tests successfully (Y/N): Y
 Verified bug fix with the described replication steps or verified the implementation meets the requirement cited (Y/N): Y
 Code coverage requirements satisfied (new code=80%, changed code=at least as high as existing) (Y/N): Y
 Code review date and attendees: Self-review by pull request
 Describe potential impact on other areas of the code: Drag-drop in directory area
 Describe any test prerequisites for this fix (e.g., restart the database): N/A
 For bugs marked "Regression - Yes", describe the cause of the regression: N/A
 Did you modify any pom.xml file? If yes, did you thoroughly document your changes and reasons? N
```

Unit tests have been amended to stay in sync with naming changes for move/copy/link actions