R1:e4806631a5b3

Use PHUIDocumentProView in Phame

Summary: Updates "View Post" to use PHUIDocumentViewPro, updates calls to `newPage` and other minor modernizations. Edit Page updated to show proper document display as well. Ref T9545

Test Plan:
Write a blog post, edit it.

{F945897}

{F945896}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T9545

Differential Revision: https://secure.phabricator.com/D14415