K8SSAND-1709 ⁃ Add task for upgrade SSTables

[burmanm]

What is missing?
When a Cassandra cluster is upgraded to a newer version which modifies the SSTable versions, we need to issue UpgradeSSTables request to the nodes so that they update the SSTables on the disk. There's currently no way to do this from the cass-operator.

Why do we need it?

Environment

• Cass Operator version:

  Insert image tag or Git SHA here

  **Anything else we need to know?**:

┆Issue is synchronized with this Jira Task by Unito
┆friendlyId: K8SSAND-1709
┆priority: Medium