Move Board Manage actions up a level

Summary: Moves "reorder columns" and "change background" up a level, redesigns "manage" page to be a little cleaner.

Test Plan: Change colors, reorder columns, manage page, disable board, re-enable board.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17879