Enhance node metrics caching

[ImNotAFrog]

What would you like to be added:
Support multiple requests in one resolution period.
Why is this needed:
I found that metrics-server does not truly cache node metrics. For example, with high-loaded cluster, part of cluster's kubelets' requests went timeout during each metrics collection (varying nodes each time) — leaving metrics-server almost unable to provide a complete set of node metrics, regardless of how the resolution is adjusted.

PS: If this proposal is adopted, I’d greatly appreciate the opportunity to participate in the modifications.

/kind feature

[k8s-ci-robot]

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