WIP infra: Add Scale Test

[vitorfloriano]

This PR adds a scale test harness to NRC.

Supersedes #185

Benchmarking plan:

Key design choices:

• Use kwokctl to create the cluster and kwok binary to simulate k8s core components to keep it lightweight (no docker/ kind overhead).
• Run the NRC as a separate binary instead of deploying to the cluster, since that would not be possible with the fake cluster created by Kwok.
• Simulate changes in conditions using Kwok's Stage CRD. See: https://kwok.sigs.k8s.io/docs/user/stages-configuration/
• Use Kwok's native Prometheus integration to keep the setup simple. See: https://kwok.sigs.k8s.io/docs/examples/prometheus/

Implementation details/Roadmap:

• Add scripts for setting up the testing environment (installing kwokctl, creating a cluster with a specified kubeconfig, installing the NRR CRD) and cleanup (deleting the kubeconfig, deleting the cluster)
• Add Ginkgo suite for installing the NRR CRs, starting the controller, simulating changes at scale with kwokctl scale and Stage CRD.
• Scrape metrics with Prometheus native Kwok integration
• Add parameters for tuning the test and controller (node count, rule count, qps, burst, max concurrency)

[kubernetes-prow]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

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[kubernetes-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[vitorfloriano]

/cc @Karthik-K-N
/cc @ajaysundark
/cc @Priyankasaggu11929

[vitorfloriano]

After much research, this is the initial work. I got a LGTM on the approach from Kwok's maintainer, so I believe I'm headed in the right direction. PTAL.