Conpherence - finesse global upload vs conpherence durable column upload

Summary: Fixes T7539. We need to set the "with-column" css class on the document body to make things like the jx-mask style-able. Also, make the global upload control only do it for the standard phabrcator page and not the document body.

Test Plan: dragged a file to conpherence column and it worked! uploaded a file to homepage with column open and it worked! uploaded a file to /file/ with column open and it worked!

Reviewers: chad, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7539

Differential Revision: https://secure.phabricator.com/D12055