Add Form MenuItem, Fix EditEngine Typeahead

Summary: Adds a FormEditEngine MenuItem for adding forms to Projects, Home, QuickCreate. Also adds an EditEngine typeahead that has token rendering issues currently.

Test Plan: Set a normal form as a menu item, edit it, set the name. Set a custom form as a menu item, edit it, set a name.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17098