Publish stories about objects in projects as related to projects

Summary:
Fixes T5456. We lost this logic in the transition to applicationtransactions.

When publishing a feed story, mark all of the object's projects as related, so the project filter in feed works.

Test Plan: Made a comment on a task associated with a project, saw the story in filtered feed.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: timor, epriestley

Maniphest Tasks: T5456

Differential Revision: https://secure.phabricator.com/D10233