Rewrite Aphlict to use Websockets

Summary:
Fixes T6559. No more flash, use Websockets. This is less aggressive than the earlier version, and retains more server logic.

• Support "wss".
• Make the client work.
• Remove "notification.user" entirely.
• Seems ok?

Test Plan:
In Safari, Firefox and Chrome, saw the browsers connect. Made a bunch of comments/updates and saw notifications.

Notable holes in the test plan:

• Haven't tested "wss" yet. I'll do this on secure.
• Notifications are too fast now, locally. I get them after I hit submit but before the page reloads.
• There are probably some other rough edges, this is a fairly big patch.

Reviewers: joshuaspence, btrahan

Reviewed By: joshuaspence, btrahan

Subscribers: fabe, btrahan, epriestley

Maniphest Tasks: T6713, T6559

Differential Revision: https://secure.phabricator.com/D11143