Allow encrypted mail to be more specific about which object is affected
In the general case, the object monogram may disclose information (#acquire-competitor) but most do not, so applications can whitelist an acceptable nondisclosing subject and link.
Support doing this, and make Differential do it. When we don't have a whitelisted URI but do know the object the mail is about, include a generic PHID-based URI; these are always nondisclosing.
- Without the Differential changes, sent normal mail (no changes) and secure mail (new generic PHID-based link).
- With the Differential changes, sent secure mail; got richer subject and body link.
Reviewed By: amckinley
Maniphest Tasks: T13151
Differential Revision: https://secure.phabricator.com/D19488