Policy - make sure "quick create" menu doesn't show up if you have nothing you can quick create

Summary: Fixes T7117. The slightly icky part is we just build the menu items up 2x because there's no way to tell you wont be able to make a menu item unless you try to make them all and come up with nada.

Test Plan: created a user and denied them access to every application in the quick create menu. observed the "+" icon disappearing from the nav, correctly. used a different, unrestricted user and the menu showed up and worked

Reviewers: epriestley, chad

Reviewed By: chad

Subscribers: Korvin, epriestley

Maniphest Tasks: T7117

Differential Revision: https://secure.phabricator.com/D11684