Allow Pholio mock images to be drag-reordered
Summary:
Ref T3640. JS part only, should give you a list in imageOrder on the server that you can read with $request->getStrList('imageOrder').
NOTE: You can't drag images into the first position; this is an existing thing that I just need to fix with DraggableList.
@chad might have some design feedback.
Test Plan: Dragged images around, things seemed to work?
Reviewers: btrahan, chad
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T3640
Differential Revision: https://secure.phabricator.com/D6729