Katello configure support for Signo

Katello can include more apps in virtual host. Foreman and Signo
will benefit from using same Apache virtual host when running on
same domain. Apache can be used to serve their static files this way.
Install Signo by katello-configure

katello-configure now installs Signo and it's Apache configuration. Once
it's installed it reloads Apache to load Signo vhost config.
Merge pull request #1 from ares/feature/signo

Signo integration