Allow XHProf profiles to be drag-and-dropped to upload them
Summary: Ref T12297. This could be fancier, but should make pulling profiles off admin.phacility.com significantly more realistic.
Test Plan: Dragged and dropped some profiles to upload them, then reviewed them via web UI.
Reviewed By: chad
Maniphest Tasks: T12297
Differential Revision: https://secure.phabricator.com/D17401