Use application PHIDs for application transactions
Summary: Ref T2715. Ref T3578. Load application transactions through application PHID infrastructure.
Test Plan: Viewed feed, saw successful loads of application transaction objects and rendered feed stories.
Reviewers: btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T2715, T3578
Differential Revision: https://secure.phabricator.com/D6617