Add back the ability to track cleanup after scale up

[burmanm]

What is missing?

In https://github.com/k8ssandra/cass-operator/issues/496 we removed the functionality that would wait for cleanup to finish after scale up before marking the process as done.

We want to return this behavior, but as an optional one.

Why is this needed?

If after scaling up (without cleanup) a scale down is used, it is possible to introduce ghost data back to the cluster.