HPA-based Autoscaling Demo

[carlydf]

[noamyehudai]

it's very necessary for us, can't wait 💪

[noamyehudai]

@carlydf do you have an ETA for it?

[carlydf]

@noamyehudai see https://github.com/temporalio/temporal-worker-controller/tree/main/internal/demo#metric-based-hpa-scaling-demo