IPA-EPN: Add tests for sending real mail with auth and templates
Send e-mail using postfix on localhost and read the contents to
verify that the mail was delivered and that the template was
applied correctly.
Fixes: https://pagure.io/freeipa/issue/3687
Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Francois Cami <fcami@redhat.com>