Umbrella issue: Onboarding ppc64le build cluster to k8s community's Prow

[Rajalakshmi-Girish]

Am Umbrella issue to track work items related to adding ppc64le build cluster to Kubernetes Prow infra.

• Create an IBM account and hand over to cncf(add them as admin)
• Create k8s cluster on ppc64le using an automation scripts(TF+ansible)
• Add the kubeconfig yaml to this GCP Secret Manager Resource
• Add created k8s cluster into community prow infra: add ppc64le cluster to prow #7862
• BOSKOS setup Update boskos deployments on ibm-ppc64le cluster #7886
• Setup ESO and external secrets fix external secrets for new cluster #7883
• Add terraform code for bringing up k8s build cluster on ibmcloud: Add terraform for provisioning power build cluster on ibmcloud #7889

Ref: sig-k8s-infra slack thread- https://kubernetes.slack.com/archives/CCK68P2Q2/p1739359083466129

[Rajalakshmi-Girish]

/cc @upodroid @mkumatag @Prajyot-Parab @Amulyam24

[kishen-v]

/cc