Investigate removing the replication settings from `createNamespace` and `createKeyspace` commands

[amorton]

these make no sense when running in Astra, I assume they are there for DSE / OSS support.

See CreateNamespaceCommand / CreateKeyspaceCommand classes , second is only added by #1397

If that is the case it is not clear in the code if they:

• are shown in the Open API spec when running in astra.
• values can be passed
• include comments that it is only available in OSS / DSE

[jeffreyscarpenter]

We don't actually expose createNamespace in Astra, so is there anything really to do here?