Add tasks.systemd_daemon_reload()
    
    systemd daemon must be reloaded after a config file is added, changed,
    or removed. Provide a common API endpoint in ipaplatform.tasks.
    
    Related: https://pagure.io/freeipa/issue/7860
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>