Support metrics-server for clusters with more then 5k nodes

[youwalther65]

Current statement in FAQ is, that metrics-server was tested with up to 5,000 nodes.

What would you like to be added:
Provide tests with even larger clusters.

Why is this needed:
Cloud providers are pushing the limits of their EKS clusters because of demanding applications. Having metrics-server support for those kind of cluster to implement v1beta1.metrics.k8s.io would help.

/kind feature

[k8s-ci-robot]

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