R1:f742d00c2894

Mostly use PhrictionContentQuery to load PhrictionContent objects

Summary: Depends on D19094. Ref T13077. Use modern infrastructure to perform these loads. I left a couple of calls in the older API methods unconverted.

Test Plan: Viewed documents. Viewed older versions. Viewed diffs. Did revert edits to older versions.

Maniphest Tasks: T13077

Differential Revision: https://secure.phabricator.com/D19095