Document how Kueue works with cluster-autoscaler

[alculquicondor]

What would you like to be cleaned:

We claim that Kueue can be used alongside CA, but we don't explain how. Perhaps a version of theory of operation in bit.ly/kueue-apis could help.

/kind documentation

Why is this needed:

We got a question in slack about this, where the user story was:

I guess my suggestion/story would be, I would like a jobs node pool in my cluster to be auto scalable with min: 0 nodes and max: (my budget limit, or a sane guardrail). And as my node pool hits its max nodes, have the jobs queue up for placement.

Which is exactly what kueue is meant to do.

[alculquicondor]

/help

[k8s-ci-robot]

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[kerthcet]

Not only cluster-autoscaler, I think we can also mention the relationship with other components, especially kube-scheduler, we have users had this confusion, see https://kubernetes.slack.com/archives/C032ZE66A2X/p1669212423358399?thread_ts=1669137423.710669&cid=C032ZE66A2X