[Feature Request] Extend FAIL2BAN_REGEX with "iot-malware download" verdict

[MikhailKasimov]

Is your feature request related to a problem? Please describe.

Block sources with potential iot-malware download verdict:

Ref: https://twitter.com/500mk500/status/1260588201787494407

Describe the solution you'd like

See https://github.com/stamparm/maltrail/blob/master/maltrail.conf#L48C16-L48C123

FAIL2BAN_REGEX attacker|reputation|potential[^"]*(web scan|directory traversal|injection|remote code)|spammer|mass scanner --> FAIL2BAN_REGEX attacker|reputation|potential[^"]*(web scan|directory traversal|injection|remote code|iot-malware download)|spammer|mass scanner

[MikhailKasimov]

Done in 720014a + minor patch for REMOTE_SEVERITY_REGEX to handle iot-malware substring.