add metrics logic to perf tests

[vepatel]

Proposed changes

Adds pod and node metrics logic to perf tests.

[
    {
        "metadata": {
            "name": "nginx-ingress-7d74b6b9fc-jj9mz",
            "namespace": "nginx-ingress",
            "creationTimestamp": "2024-03-08T14:18:27Z",
            "labels": {
                "app": "nginx-ingress",
                "app.kubernetes.io/name": "nginx-ingress",
                "app.kubernetes.io/version": "3.5.0",
                "app.nginx.org/version": "1.25.4",
                "pod-template-hash": "7d74b6b9fc"
            }
        },
        "timestamp": "2024-03-08T14:18:19Z",
        "window": "24.379s",
        "containers": [
            {
                "name": "nginx-ingress",
                "usage": {
                    "cpu": "74155994n",
                    "memory": "19628Ki"
                }
            }
        ]
    }
]

[
    {
        "metadata": {
            "name": "gke-venktesh-test-default-pool-80cf31c5-5rx7",
            "creationTimestamp": "2024-03-08T14:18:27Z",
        },
        "timestamp": "2024-03-08T14:18:16Z",
        "window": "30.169s",
        "usage": {
            "cpu": "404319897n",
            "memory": "1189960Ki"
        }
    }
]

Checklist

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork