phabricator: add a "phabstatus" template keyword We add a "phabstatus" template keyword, returning an object with "url" and "status" keys. This is quite similar to "phabreview" template keyword, but it queries phabricator for each specified revision so it's going to be slow (as compared to the "phabstatus" show view from previous changeset). Differential Revision: https://phab.mercurial-scm.org/D7507