Merge remote-tracking branch 'ispc/master' into new-layout-3.1

interface/web/admin/form/users.tform.php

interface/web/admin/lib/lang/de_users.lng

interface/web/admin/lib/lang/en_users.lng

interface/web/admin/templates/users_user_edit.htm

interface/web/dns/dns_soa_edit.php

interface/web/login/lib/lang/de.lng

interface/web/login/lib/lang/en.lng

interface/web/login/password_reset.php

interface/web/mail/mail_domain_dkim_create.php

server/lib/classes/cron.d/500-backup.inc.php

server/lib/classes/cron.d/500-backup_mail.inc.php

server/lib/classes/system.inc.php

server/plugins-available/apache2_plugin.inc.php

server/plugins-available/backup_plugin.inc.php

server/plugins-available/mail_plugin.inc.php

server/plugins-available/nginx_plugin.inc.php