Function get_nxdomain_nodata_soa

pub fn get_nxdomain_nodata_soa<'a>(
    question: &Question,
    response: &'a Message,
    current_match_count: usize,
) -> Option<&'a ResourceRecord>

Check if this is an NXDOMAIN or NODATA response and return the SOA if so.

Also sanity checks that the SOA record could be authoritative for the query domain: the domain has to be a subdomain of the SOA, and the SOA has to have at least the current match count.