R1:f910e38ecc1b

Provide a mobile application menu

Summary:
Adds a right-hand-side application menu, based roughly on `frame_v3.png`.

This has the same icon as the left menu until we get real design in, but is functionally reasonable.

Test Plan: {F26170} {F26169}

Reviewers: chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T1960

Differential Revision: https://secure.phabricator.com/D4061