Issue Description: 

We need to install ArgoCD into the prod data plane and ensure that it syncs the overlays/prod overlay from the prod branch of our GitHub repo. 

Sync should be set to manual as we only want manual rollout of deployments to the data plane.

Acceptance Criteria: 

• ArgoCD is installed into the prod data plane
• ArgoCD is configured to sync the overlays/prod kustomize overlay
• ArgoCD is configured to sync manually
• Endpoint for ArgoCD is updated into our environment file