Spamhaus DROP list implementation

Right now is very raw and it simply compares prefixes, however sometimes a /24 can be on the DROP list, while IRRd outputs a /22. So we have to build something that searches in larger prefixes.

Reference: https://github.com/eranium/filtergen/commit/8870c65b3c31cb6eab1921e4d234e68ea701b80f