[FEAT] Option to Always Send Notifications

[redge76]

Hi, and thanks for the great project!

Could you add a configuration option that allows Scrutiny to send periodic notifications even when no disk issues are detected?

This would enable compatibility with push‑based monitoring tools like Uptime Kuma, which require regular “success” heartbeats (otherwise they send an alert. This enable to receive alerts scrutiny breaks).

I imagine this could be implemented by adding a new "success" value to the NotifyLevel enum, and having ShouldNotify return true when
(device.DeviceStatus == pkg.DeviceStatusPassed) or (config.NotifyOnSuccess == true),
or something similar.

Thanks for considering this!