Create new k8s 1.25 CI Cluster for testing

Summary

Bring up a new K8S 1.25 CI Cluster for us to start running tests against. See gitlab-org/charts/gitlab#3018 (closed) for the previous time we set this up.

TODO

• Determine variable settings to deploy cluster
• Deploy cluster
• Set up cert-manager
• Set up external DNS
• Disable auto-upgrade
• Copy kubeconfig artifact to 1Password Cloud Native:cloud-native-v125 credentials
• Update https://gitlab.com/gitlab-org/distribution/infrastructure/kube-agents to add agent for cluster to monitor https://gitlab.com/gitlab-org/charts/gitlab
• Install agent in cluster.