Backup encryption required for firewalls with a subscription

[cotosso]

Firewalls with active subscription currently send their backup to Nethesis Operation Center, regardless the fact they are encrypted or not.
To promote best practices in cybersecurity measures and enhance data protection I propose to send backups only if they are encrypted with a passphrase.

Proposed solution
Ensure backups are transmitted to the Service Center only if they are encrypted.

If the firewall has an active subscription and the passphrase is not configured:

• Display a notification in the Dashboard informing the user that backup transmission is currently suspended.
• Send information to the Nethesis Operation Center indicating whether the passphrase is configured or not (there is already an issue for that: Inventory: add backup passphrase status (set/unset) #988)