Zuul v3 has a zuul-web service that provides web streaming and
eventually other web content. Add support for running it. Also add it to
the Apache mod_rewrite proxy info.
While we're adding things, add proxy info for plugin connections, which
should allow receiving github webhook events.
Change-Id: Ic79681b287dbd1a44469da70c680060940734f40
3f4f1d9820