[gitlab-org runners] 1 create new GCP projects for the ephemeral VMs

This issue is concerned about creating the Infra in terraform.

The main steps would include:

• Create new project definitions 👉 https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/5846
  • Ensure projects are created in GCP 👉 https://console.cloud.google.com/welcome?project=r-saas-l-m-amd64-gitlab-org-1
• Document the new CIDRs in the Runbooks 👉 gitlab-com/runbooks!5843 (merged)
• Create environment definition + TF CI/CD (example) 👉 https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/5885
  • follow up fix 👉 https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/5896
    • follow up 2x fix 👉 https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/5900

Other goals I'd like to accomplish in this iteration:

• Refactoring TF definitions for the new environment.
• Automating as much work as possible.