Transactions - add "and X others" dialog support to application transactions

Summary: Fixes T4430. Basically does a little code massage from the new stuff in D8525 and application transactions to get this working. Adds a new controller to the subscriptions app to make rendering these pretty easy peasy.

Test Plan: Used my test task in D8525 to verify both add and rem versions of these dialogs worked correctly.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, chad, Korvin

Maniphest Tasks: T4430

Differential Revision: https://secure.phabricator.com/D8540