Make status.o.o header and footer reusable

Externalize the top menu and footer section of status.openstack.org so
that it can be reused by child pages without them having to know about
each other. Fixes bug 1129239.

Note: this does not make child pages other than the default page use the
reusable header/footer: that should be pushed in subsequent commits.

Additionally, clean up unused .js links that result in 404s.

Change-Id: I75e2d827648cb648a2887f4b036342f18690ab92
Reviewed-on: https://review.openstack.org/25530
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins