DNSListener IPv6 AAAA request support

[strictlymike]

Matt Williams proposes DNS IPv6 AAAA request support. This ticket proposes a code snippet for consideration (credit: Matt Williams). We should also add a test to the test suite and perform one-time validation using a native sample if one can be found.

elif qtype == 'AAAA':
    for addrinfo in socket.getaddrinfo(socket.gethostname(), 0, socket.AF_INET6):
        sockaddr = addrinfo[4]
        address = sockaddr[0]
        if '%' in address:
            address = address.split('%')[0]
        
        self.server.logger.debug('Responding with \'%s\'',
                                  address)
    
        response.add_answer(RR(qname, getattr(QTYPE,qtype), rdata=RDMAP[qtype](address)))
        break