Run CI jobs in kubernetes

⚠️ This MR is part of a series:

• Migrate Kubernetes integration tests to use the... (gitlab-org/gitlab-runner!5175 - merged) • Georgi N. Georgiev | GitLab • 17.7
• Improve Operator installation and add GKE features (gitlab-org/ci-cd/runner-tools/grit!124 - merged) • Georgi N. Georgiev | GitLab • 17.10
• https://gitlab.com/gitlab-org/ci-cd/runner-tools/runner-kubernetes-infra/-/merge_requests/1+s
• Remove test dirs and flatten operator modules (gitlab-org/ci-cd/runner-tools/grit!146 - merged) • Georgi N. Georgiev | GitLab • 17.10
• Allow deploying multiple runners in a single k8... (gitlab-org/ci-cd/runner-tools/grit!147 - merged) • Georgi N. Georgiev | GitLab • 18.1
• https://gitlab.com/gitlab-org/ci-cd/runner-tools/runner-kubernetes-infra/-/merge_requests/2+s
• Run CI jobs in kubernetes (!504 - merged) • Georgi N. Georgiev | GitLab • 17.9 (You are here)

⚠️

What does this MR do?

Uses a runner deployed in the Kubernetes cluster to run non-dind jobs.

Forked pipeline runs were tested in !509 (closed). Forks will continue using the gitlab-org runners, while our own pipelines will use the kubernetes runner.

Why was this MR needed?

RunnerKubernetes Dogfooding

What's the best way to test this MR?

CI should pass and it should show that the kubernetes runner is being used.

What are the relevant issue numbers?

Closes gitlab-org/gitlab-runner#38453 (closed)