Let's simplify things and only maintain a single RR key per transaction
object, instead of a full DnsQuestion. Unicast DNS and LLMNR don't
support multiple questions per packet anway, and Multicast DNS suggests
coalescing questions beyond a single dns query, across the whole system.
Let's optimize things a bit and properly compare DNS question arrays,
instead of checking if they are mutual supersets. This also makes ANY
query handling more accurate.