Scale up apiserver #26
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This PR follows up on #25 (7899b35 to be precise), where kube-apiserver was scaled down to a single instance as API request distribution across instances would vary between experiment runs.
Background: due to the simple SNI passthrough mechanism of Gardener, all API requests from a single controller land on a single API server instance as all reuse a single TLS/h2 connection.
However, the load test experiments hit a single API server's limits pretty quickly.
Instead of using a single instance, go back to 4 instances and disable HTTP/2 instead.
With this, we go back to pooling TLS connections for sequential reuse in multiple HTTP/1.1 requests.
This ensures a much more even distribution across API servers with a small performance penalty, which is good enough for reproducible evaluation results.
Also, this PR fixes two minor issues in the dev setup and upgrades the hosting cluster to 1.26.