Allow subnets in whitelist/blacklist commands

[depwl9992]

I have the plugin setup to try geolocating every address. However, for obvious reasons, LAN subnets are unfindable by geoip,

Additionally, I have turned down the DDOS detection to 1 connection per second (highlighting a different issue: a frequency of 1 always triggers even on the first connection, and has no basis for calculating the frequency because there is no second connection attempt).

Thus, I was blocked until I whitelisted my local IP.

Allowing CIDR blocks (e.g. whitelist add 192.168.10.0/24) would be particularly useful so I don't have to manually whitelist all 254+ IP addresses that would be allowed on a LAN or other IP blocks.