Automation of Synthetic Load Tests

[Vedran Lerenc]

What would you like to be added:
Measure CPU and memory footprint, measure disk and network throughput and latency, measure API server and ETCD throughput and latency of our shoot clusters automatically, so that we do not miss regressions.

Why is this needed:
We sometimes miss regressions that the current tests do not catch.

⚠️ Note: Avoid duplicating the Kubernetes performance tests: https://github.com/kubernetes/perf-tests

[Kesavan]

@vlerenc
we are using the community framework for perf-tests and kubetest to execute performance tests and coming up with similar perf-dashboard

Contribution for Gardener Provider can be found in this fork.