Add option --delete to rsync command used in migrate

[rjmateus]

With the introduction of the prepare command we can start to copy and some changes can still happen on the source server. We should consider add the --delete option to rsync to make sure we remove any file from the target server that may have ben removed from the source server in the meantime.

We need to make sure it will not remove any new file that was introduced with the containerization version.