R1:cba5a866f83a

Consistent panels for account settings.

Summary: Sets all panels to full width and no backgrounds in settings for consistency.

Test Plan: Check each page width.

Reviewers: epriestley, codeblock, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4460