Existing methods will need support to target K8ssandraCluster also

[burmanm]

Most of the methods in k8ssandra-client only accept target CassandraDatacenter at the moment to fetch a pod. We should add support for K8ssandraCluster objects also and fetch a CassandraDatacenter if possible.

There are certain edge cases which we need to verify. Targeting control plane without any deployed CassandraDatacenters would result us in needing to switch context and target a data-plane instead. This isn't necessarily available to the user however.

┆Issue is synchronized with this Jira Task by Unito
┆Issue Number: K8CL-4