Ability to archive Phame Posts
Summary: Ref T9897. Adds ability to Archive a Phame Post (only visible under ApplicationSearch).
Test Plan: Archive a post, re-publish it, search for it, archive it again. View Home, Blog, Live pages.
Reviewed By: epriestley
Maniphest Tasks: T9897
Differential Revision: https://secure.phabricator.com/D16104