Enable kubernetes_node_scale benchmark (up to 5k nodes) on AWS EKS with Karpenter

[kiryl-filatau]

Summary

Enables running the kubernetes_node_scale benchmark (0→5k→0→5k nodes) on AWS EKS with Karpenter. The benchmark scales a deployment with pod anti-affinity, measures scale-up/scale-down and a second scale-up, then tears down the cluster.

Main changes

• Kubernetes_node_scale benchmark: Template and scaling logic (scale up, scale down, phases), metrics collection, and timeouts tuned for large runs.
• EKS + Karpenter: Nodepool template (instance types including t, higher CPU limit), EKS/Karpenter cluster lifecycle and cleanup.
• Teardown robustness: Orphan ENI deletion in _CleanupKarpenter — retry with backoff on AWS throttle (RequestLimitExceeded), treat “ENI not found” as success; uses suppress_failure for these cases.
• Tracker: Single get nodes pass in _StopWatchingForNodeChanges; resolve machine type only for current nodes, use "unknown" for others to avoid thousands of kubectl calls on 5k-node runs.

NOTE: Hardcoded values to be updated