Store proxied DNS responses as raw bytes

[mafik]

Currently Gatekeeper parses processed DNS records & re-encodes them when sending to clients. This breaks DNS compression in record types not understood by Gatekeeper. So far all of the problematic record types have been fixed but it's possible that new or unknown record types will cause errors again. To bypass this issue, Gatekeeper could store the raw, unprocessed DNS records in each Entry. Those raw DNS records could then be sent to clients without any additional processing.