add paramter 'mail-notify' to froxlor:update CLI script to notify the system administrator via email about a new version (once per version)

Signed-off-by: Michael Kaufmann <d00p@froxlor.org>

install/froxlor.sql.php

@@ -700,6 +700,8 @@ opcache.validate_timestamps'),
 	('system', 'acmeshpath', '/root/.acme.sh/acme.sh'),
 	('system', 'distribution', ''),
 	('system', 'update_channel', 'stable'),
+	('system', 'updatecheck_data', ''),
+	('system', 'update_notify_last', '0.11.0-dev1'),
 	('api', 'enabled', '0'),
 	('2fa', 'enabled', '1'),
 	('panel', 'decimal_places', '4'),