Add Email Notification For License Issues To Prevent Backup Failure

[planedrop]

First issue report on Github so apologies if anything here isn't formatted the way people prefer.

Recently I had Vates make some adjustments to our licenses to follow the new bundled license structure, everything was great on that front, but when the license change happened, it de-activated my previous one for XOA.

This de-activation resulted in my backups failing (as expected since it wasn't licensed), but no email was sent to me about the backup failure (since it was due to license expiry). I caught this very quickly since I normally expect success emails every night, but I can see a situation where someone only sets up failure notifications so they don't think anything is wrong.

I think XOA should be configured to, at the very least, send emails (daily maybe?) about expired licenses so admins know when this is happening.

Or maybe configure it so backup failures, even due to license expiry, still send an email about the failure.

While admins should know to go in and apply their new license whenever they make changes, we all can get busy so it could be easy to miss.