Making DifferentialListController more mobile-friendly

Summary:
We now have the app menu top-right, so we don't need the side navbar anymore

Refs T2014

Test Plan: Visited list view in narrow / wide browser. Could access everything either directly (tables :P) or the top right menus

Reviewers: epriestley, chad

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2014

Differential Revision: https://secure.phabricator.com/D5728