Drive Herald edits via transactions
Summary: This is kinda bad in terms of UI (It just makes a json of the thing and diffs that), but it's a start.
Test Plan: edit rule, create rule, add/remove/edit conditions, actions
Reviewers: Blessed Reviewers, epriestley
Reviewed By: Blessed Reviewers, epriestley
Subscribers: Korvin
Differential Revision: https://secure.phabricator.com/D15542