Touch up notification/messages panels

Summary: Fixes T5575. Moves "All" links into title/header. Mark all read floats left, and connection status sits in footer. Also added hints to enable notifications (it's a cool feature).

Test Plan:
Tested locally both menus.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T5575

Differential Revision: https://secure.phabricator.com/D10269