Use Application PHIDs in Ponder

Summary: Ref T2715. Switch Ponder to the new IDs.

Test Plan: Ran `phid.lookup`; `phid.query`. Grepped for old constant

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2715

Differential Revision: https://secure.phabricator.com/D6554