[Podified] Create autoscalers for all workers

[Fryguy]

In podified we should add the ability to autoscale workers based on CPU/Memory and arbitrary metrics (like queue depth). When we can autoscale we should prefer that over our settings based worker counts.

• Horizontal Pod Autoscalers - https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/
• Autoscaling on custom metrics - https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/#autoscaling-on-metrics-not-related-to-kubernetes-objects

Some other considerations

• UI will probably need to disable parts of the UI when autoscaling is in effect, and grey out the worker count (perhaps show "autoscaling")

@miq-bot add-label enhancement

cc @jrafanie

[miq-bot]

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