Fixes #7636: Add Katello Disconnected user guide.

# rpm -Uvh http://yum.theforeman.org/1.6/el6/x86_64/foreman-release.rpm
Retrieving http://yum.theforeman.org/1.6/el6/x86_64/foreman-release.rpm
curl: (22) The requested URL returned error: 404 Not Found
error: skipping http://yum.theforeman.org/1.6/el6/x86_64/foreman-release.rpm - transfer failed