Server Roles: make *config-show consume relevant roles/attributes
    
    This patch modifies config objects so that the roles/attributes relevant to
    the configuration are shown in the output:
    
    * config-{show,mod} will show list of all IPA masters, CA servers and CA
      renewal master
    
    * dnsconfig-{show,mod} will list all DNS server and DNS key master
    
    * trustconfig-{show,mod} will list all AD trust controllers and agents
    
    * vaultconfig-show will list all Key Recovery Agents
    
    http://www.freeipa.org/page/V4/Server_Roles
    https://fedorahosted.org/freeipa/ticket/5181
    
    Reviewed-By: Jan Cholasta <jcholast@redhat.com>
    Reviewed-By: Martin Basti <mbasti@redhat.com>
    Reviewed-By: Pavel Vomacka <pvomacka@redhat.com>