R1:0a554c2ed535

Allow profile menus to be collapsed and expanded

Summary:
Ref T10054. I think this gets everything except:

- circles on icons;
- I spent ~15 minutes poking at animations but wasn't able to get anything that looked reasonable whatsoever.

Test Plan:
- Collapsed menus.
- Expanded menus.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10054

Differential Revision: https://secure.phabricator.com/D15056