Lost Status updates, add datacenter contextName

[burmanm]

What happened?
ContextName is missing from our Datacenter status, so if the user deletes the datacenters[] part of the DC, we can no longer necessarily pick up the correct target context.

As for missing status updates, there are a lot.

In the datacenters.go, we don't actually use the updated value of kdcStatus, we simply copy stuff to it but do not reassign that new value (since a new reference was created with := earlier). As such that status update is entirely lost.

In reaper.go and stargate.go, we update the entire Status part and then miss any fields that might have been set previously. This was clear when I modified the tests to check status fields and they were not there when 10 seconds earlier those fields were there (such as the context). Thus, we need to copy the Stargate info to existing Status, not overwrite the entire Status with just what Stargate had in mind. Also, some updates in the stargate.go were also missing due to the same issue as in datacenters.go, where the new reference was never actually set back to the kcObject.Status.

Did you expect to see something different?

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

Environment

• K8ssandra Operator version:

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• Kubernetes version information:

  kubectl version

• Kubernetes cluster kind:

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• Manifests:

insert manifests relevant to the issue

• K8ssandra Operator Logs:

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Anything else we need to know?:

┆Issue is synchronized with this Jira Story by Unito
┆Issue Number: K8OP-300