Update Ponder Answer layout

Summary: Ref T9099, A step forward for the main Ponder UI. Mostly moving stuff into View classes and reducing clutter. Took a pass at keeping comments and helpfuls, but unclear what the 'final' UI will be (I'm just designing as I use the product).

Test Plan:
Review a number of questions and answers.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T9099

Differential Revision: https://secure.phabricator.com/D13872