Don't add `noise` to the output file about dnscan

[AlexanderMac]

Cool, thank you for this change.

[rbsec]

Looking at your fork, am I correct in thinking that you essentially want an option that disables all of the checks other than the axfr and subdomain grinding, and that only prints subdomain - ip in the output file?

[AlexanderMac]

Exactly, only subdomain - ip. But I don't suggest adding a new option, I think that it would be ideal to write only subdomain - ip to output file.

[rbsec]

I'm not keen on making that the default mode - even though not everyone is interested in the NS/TXT/MX/DNSSEC/etc scans, they provide a lot of valuable information, and I don't like making major changes to the default behaviour that people's workflows (including my own) rely on.

I've added a -q / --quick mode in 5a48a3e which disables everything other than the zone transfer and subdomain scanning, and reduces the file output (assuming you specify -o) to just subdomain - ip - hopefully this meets your objective.