Move existing "Console" interfaces away from "setFixed(...)" on "TwoColumnView"

Summary: Depends on D20931. Ref T13362. Move all "Console"-style interfaces to use a consistent layout based on a new "LauncherView" which just centers the content.

Test Plan: Viewed all affected interfaces.

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam

Maniphest Tasks: T13362

Differential Revision: https://secure.phabricator.com/D20933