medusa calculates podNames incorrectly when unbalanced racks are used

[burmanm]

What happened?
medusa's hostmap.go assumes evenly balanced racks, but this is not necessarily true. Given the size of 8 and 3 racks, the StS would end up with sizes 3,3,2 and this is fully functional. Yet, Medusa would believe this is actually 3,3,3 since it only divides and rounds.

Did you expect to see something different?

How to reproduce it (as minimally and precisely as possible):

Environment

• K8ssandra Operator version:

  Insert image tag or Git SHA here

• Kubernetes version information:

  kubectl version

• Kubernetes cluster kind:

  insert how you created your cluster: kops, bootkube, etc.

• Manifests:

insert manifests relevant to the issue

• K8ssandra Operator Logs:

insert K8ssandra Operator logs relevant to the issue here

Anything else we need to know?:

┆Issue is synchronized with this Jira Story by Unito
┆Issue Number: K8OP-298