rename response_length to response_size

[rghvdberg]

The docs https://www.shadowserver.org/what-we-do/network-reporting/open-ms-sql-server-resolution-service-report/ state
that there's a field called response_length, however in de sample at the bottom of the page and in the csv report we received the field is named response_size.

[kruisdraad]

rejected change

although it makes sense now, the field was other in the past. IF you ever want to add old reports back it would fail. This is why we have ALIAS method inside the definition. Have a look at the botnet_drone currently configured. This way both old and new will still work. Please update your PR to be accepted.