Remove various unused beahviors from PHUIWorkboardView
Summary: Ref T5240. We don't currently use any of these options and I don't think we have any plans to use them. Strip them out for now to make fixing drag-and-drop stuff easier.
Test Plan: Grepped for removed stuff, no hits.
Reviewed By: chad
Maniphest Tasks: T5240
Differential Revision: https://secure.phabricator.com/D14864