Implement a new IPA command allowing to retrieve the list of users matching
the provided certificate.
The command is using SSSD Dbus interface, thus including users from IPA
domain and from trusted domains. This requires sssd-dbus package to be
installed on IPA server.
https://fedorahosted.org/freeipa/ticket/6646
Reviewed-By: David Kupka <dkupka@redhat.com>
Reviewed-By: Jan Cholasta <jcholast@redhat.com>