Add routes to power our custom Status Board app

Summary:
At the hackathon, Matt W. and I developed these routes to provide data
that can be consumed by the Status Board app (panic.com/statusboard/).

Test Plan:
I diffed the output of these routes against the output from Matt's
fork of the analytics repository which we were using during the hackathon.
I also checked the widgets in my local browser.

Reviewers: robert, matt

Reviewed By: matt

CC: matt

Differential Revision: http://phabricator.khanacademy.org/D3173