Add option to blacklist certain URLs

[jbargu]

A PQL definition could currently access data on the local network, which could potentially open up opportunities for certain vulnerabilities on the local network. Research the repercussions of not having any filters (possible redirection as well) and implement an API for disabling certain URLs. By default all LAN/localhost traffic should be blocked to avoid this. User could then enable the URLs through config variables (probably a list of regex).