Update Phurl for modular transactions
Summary: Ref T6049. This moves Phurl to modular transactions.
Test Plan: Everything works here, add phurl, edit phurl, use phurl. Test various error states. Left a TODO on the validate dupe keys, not sure how to implement that in modular-land.
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin
Maniphest Tasks: T6049
Differential Revision: https://secure.phabricator.com/D17405