Change Skynet Blacklist to be a Hash
Right now the Skynet blacklist is just a list of Skylinks. Which is pretty amusing, because the same list that's supposed to prevent people from accessing content also tells them exactly where to find the content if they run their own node.
This is probably not the best approach. We should update the blacklist so that it is the hash of the banned skylink, instead of the skylink itself we store the hash of the Merkle root, which means someone looking at a list of banned content can't go and access it themselves.
This is going to require compat code as well, we're going to need to take the current blacklist on disk and update it to be storing hashes.
This is technically a breaking change for the API because the /blacklist endpoint is going to be returning something different. the POST calls should stay the same though.