Add ipv4 range, cidr, prefix observable support. #85
Description
We should be able to support ipv4 ranges, cidrs, and routing prefixes.
Examples:
- Ipv4 Range: 10.0.0.0-10.0.255.255
- Cidr: 192.168.3.0/24
- Prefix : 172.16.0.0., Length: 12
Given that all of these represent ranges of IP numbers (they each have a 'beginning' and an 'end'), the easiest thing we can do is represent them as such. Since this is reversible, nobody should bug out over it.