[feat] Denylist, add CIDR range block and ASN block

[fimmspin]

I think it could be good to add possibility of blocking CIDR ip ranges and, if possible, entire ASN.

For example, i see many spam msgs arrive now from:
AS25693
Virtual Machine Solutions, LLC
-no reverse hostname
-always different IPs
*Not blocked by FWD

AS36352
Hostwinds Seattle
*currently blacklisted by FWD as gta5menuclub.com hostname.