Remove quick create buttons from application launcher
Summary: Ref T3623. These are obsoleted by the global quick-create menu, so we can simplify the app launcher.
Test Plan: Looked at app launcher, grepped for everything.
Reviewers: chad
Reviewed By: chad
CC: chad, aran
Maniphest Tasks: T3623
Differential Revision: https://secure.phabricator.com/D8104