Add skip change DNS to transfer tool

Hello,

As a web-hosting provider i think we can improve the current transfool to work better with large accounts that need to be tested and configured after a transfer.

Could you please add the option to skip change DNS to the transfer tool? With very large accounts the transfertool gives downtime. Sometimes with need to move websites to different servers. The transfer tool gives downtime as DNS is changed on a cluster. We need to transfers accounts with almost zero downtime. example: copy a very big account to a new server, check if everything works, like varnish, custom settings -> then do a manual final rsync and database transfer. -> then we change DNS after developer and customer acceptance.

This is not possible at the moment and we need to make all kinds of workarounds to make the downtime a less as possible. The current transfertool works well for small customers or when the DNS is not on the same cluster.

Best regards.

Wietse D.