Implement "replace" transactions in Pholio without "applyInitialEffects"
This creates some problems today where I'd like to get rid of applyInitialEffects for MFA code. In the future, it creates a problem becuase there's no way to pass an entire Image object over the API.
Instead, create the Image first, then just provide the PHID. This is generally simpler, will work well with the API in the future, and stops us from needing any applyInitialEffects stuff.
Test Plan: Replaced images in a Pholio mock.
Reviewed By: amckinley
Maniphest Tasks: T11351
Differential Revision: https://secure.phabricator.com/D19924