status.tpo needs a layout for 404s

In #3 (closed) we discovered that services with no incident history (i.e. those that are effectively "empty") 404 on click. Although it's not the best UX, it seems to be how cstate works.

However it doesn't look like we have a 404 page set up, although there is a layout for it on github: https://github.com/cstate/cstate/tree/master/layouts