(tarball): Improve lookup error handling in DnsResolver

[clemgbld]

Improve DnsResolver error handling.

• We should find a way to log an error when a lookup fail with the Logger class from the scanner.

• figure it out what to do based on the error code :
  probably return true on those : ( "NOTFOUND", "BADNAME", "NONAME", "BADSTR", "REFUSED", "SERVFAIL") to flag the hostname as a shady link.
  and false for any other.

the docs of the error code.