Add a jinja2 e-mail template for EPN
    
    Add options for character set (default utf8) and message
    subtype (default plain). This will allow for more control
    for users to do either HTML mail or use ascii for the character
    set so the attachment is not base64-encoded to make it easier
    for all mail clients.
    
    Collect first and last name as well for each user in order to
    provide more options for the template engine.
    
    Make the From address configurable, defaulting to noreply@ipa_domain
    Make Subject configurable too.
    
    Don't rely on the MTA to set Message-Id: set it using the email
    module.
    
    Fixes: https://pagure.io/freeipa/issue/3687
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Michal Polovka <mpolovka@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Michal Polovka <mpolovka@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>