[Scenario] Add explanation to repository move dialog

Provide instructions for how to undo changes made
when dragging components from one repository to
another (this is a move operation, whereas the
gesture normally represents a link, so explanation
is necessary to ensure that the user understands
what has happened.)
[Scenario] Simplify/organize repository move dialog summary
[Scenario] Prevent close of repository move dialog

Prevent the repository move dialog from being
closed before the move is complete. This ensures
the user sees appropriate notification and that
the user is no able to continue editing while
the move is still in progress.
[Scenario] Provide fallback text for repository move dialog

When no objects have been moved after completing a drop
to a repository, simply dispose the dialog quietly.

If objects have been moved but an exception occurs on
the worker thread for some reason, fall back to less
informative generic dialog text.
[Scenario] Move repository move dialog strings to bundle