Refactor / Cleanup / Simplify a bunch of dnd related rendering / animation

Addresses:
=> Fix folder icon drop location mapping (was very far off)
=> Fix BubbleTextView drop animation shifted by a few pixels
=> Get rid multiple unnecessary calls to setDragMode(none), was breaking
   some of the reorder flow; still some issues to address here.
=> Fix folder icon parallax (didn't work when the folder had a dot)

Test: manual

Change-Id: I5959cf341996f75d30212353ec096ed25bf40ea5