Support sending multiple OpenID AX values
This allows us to send list a list of attribute values in a standard compliant
method.
We now process the number of requested values of any requested attribute,
and only send up to the maximum requested number.
Signed-off-by: Patrick Uiterwijk <puiterwijk@redhat.com>
Reviewed-by: Pierre-Yves Chibon <pingou@pingoured.fr>