Add a quote action to Differential and Maniphest

Summary:
Ref T4119. This is ugly for now, but technically works.

The comment area and transaction log don't realy know about each other, so for the moment the linking is a bit manual. Differential/Maniphest are special cases anyway.

Test Plan:

Reviewers: chad, btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T4119

Differential Revision: https://secure.phabricator.com/D8957