Summary:
Ref T4010. Projects have a weird proto-version of ApplicationTransactions which is very similar but not quite the same.
Move the storage to a modern format, but keep all the other code for now.
Test Plan: Migrated project transactions; edited projects.
Reviewers: btrahan, chad
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T4010
Differential Revision: https://secure.phabricator.com/D7370
