Add validation for public IP addresses

[biancarosa]

While looking at the IPV4 validator, it looks like we could benefit to a validation using the https://docs.python.org/3/library/ipaddress.html#ipaddress.IPv4Address.is_private function to check if the IPAddress provided is public or not.

I was thinking of a kwarg named public just like the one used on the URL validator. Does that sound useful?