Remove Konami code easter egg

Summary:
This is cool in theory, but has broken like 5 times and is broken now too. The CSS magic just isn't robust enough to keep up with CSS changes.

Just strip it out for now; if we come up with some more durable replacement we can put that back in its place.

Test Plan: Typed konami code, page didn't break horribly.

Reviewers: chad, btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D12039