Summary: Ref T3583. This doesn't add any dashboard/panel-specific code beyond headers/titles/buttons/etc., but allows you to create and view dashboards and panel skeletons.
Test Plan: See screenshots.
Reviewers: btrahan, chad
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T3583
Differential Revision: https://secure.phabricator.com/D8131
