Add a 404 catch-all with our response

In addition to setting the 404 error code in the header, we need to also
respond with our json-style error messages reporting a 404.

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Add /1.0/containers/<name> to rest api

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Switch the operation url format back

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>