R1:33c534f9b74f

Extend Config to full-width

Summary:
Ref T13362. Some applications moved to fixed-width a while ago but I was generally unsatisfied with where they ended up and have been pushing them back to full-width.

Push Config back to full-width. Some of the subpages end up a little weird, but this provides more space to work with to make some improvements, like makign `maniphest.statuses` more legible in the UI>

Test Plan: Grepped for `setFixed(`, updated each page in `/config/`. Browsed each controller, saw…