Use setDrag UI for reordering workboard columns

Summary: This UI can use the setDrag call to reduce clutter on the reodering dialog.

Test Plan:
Reorder some columns, save.

{F4959906}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17898