Automatically support "Add Projects" in Herald for all relevant objects
Summary: Ref T7849. If the adapted object implements PhabricatorProjectInterface, support the ADD_PROJECTS action.
Test Plan:
- Wrote a Differential rule with "Add Projects".
- Updated a revision.
- Got projects added.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T7849
Differential Revision: https://secure.phabricator.com/D12504