Extend Config to full-width
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 workable full-width UIs.
Maniphest Tasks: T13362
Differential Revision: https://secure.phabricator.com/D20925