Update Diffusion File UI for single column

Summary: Moves browseFile to single column, implements Owners as a list under the file (and now directory as well), improved information listed in Owners, and moves actions into the Diffusion action bar instead of the header.

Test Plan:
Test browsing directories, files, text, images, binaries, enabling blame. Mobile and desktop.

{F5111045}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D18448