R1:d3fd79057492

Add basic support for new navigation menu

Summary:
Add a new left-side application menu. This menu shows which application you're in and provides a quick way to get to other applications.

On desktops, menus are always shown but the app menu can be collapsed to be very small.

On tablets, navigation buttons allow you to choose between the menus and the content.

On phones, navigation buttons allow you to choose between the app menu, the local menu, and the content.

This needs some code and UI cleanup…