rhnreg_ks command allows users to manage registration to a Red Hat
Network (RHN) (e.g. rhn.redhat.com) server.  The moduel will also
interact with the specified RHN system via XMLRPC as needed.

Before proceeding with registration, the rhnreg_ks module will enable
the system to receive updates from RHN.  This involves enabling the
appropriate RHN yum plugin, as well as disabling an active
subscription-manager yum plugin.

Once enabled, the module will support the following operations:
 * configure
 * register
 * subscribe to custom child channels (see `rhn-channel` command)
 * unregister