In case an ID override was created for an Active Directory user in the
default trust view, allow mapping the incoming GSSAPI authenticated
connection to the ID override for this user.
This allows to self-manage ID override parameters from the CLI, for
example, SSH public keys or certificates. Admins can define what can be
changed by the users via self-service permissions.
Part of https://fedorahosted.org/freeipa/ticket/2149
Part of https://fedorahosted.org/freeipa/ticket/3242
Reviewed-By: Martin Babinsky <mbabinsk@redhat.com>
