Added mail domains

interface/lib/classes/listform_actions.inc.php

interface/lib/classes/tform.inc.php

interface/lib/classes/tform_actions.inc.php

interface/sql/auth_sql_snippet.sql

interface/sql/ispconfig3db.sql

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

interface/web/admin/lib/module.conf.php

interface/web/admin/list/server.list.php

interface/web/admin/server_del.php

interface/web/admin/server_list.php

interface/web/admin/templates/server_list.htm

interface/web/sites/form/mail_domain.tform.php

interface/web/sites/lib/lang/en_mail_domain.lng

interface/web/sites/lib/lang/en_mail_domain_list.lng

interface/web/sites/lib/module.conf.php

interface/web/sites/list/mail_domain.list.php

interface/web/sites/mail_domain_del.php

interface/web/sites/mail_domain_edit.php

interface/web/sites/mail_domain_list.php

interface/web/sites/templates/mail_domain_edit.htm