Create the foundational infrastructure to enable control plane components in HyperShift clusters to register their metrics endpoints and expose them through a single, RBAC-protected endpoint on the data plane. This enables hosted cluster users to access control plane metrics through their standard monitoring tools.

  Acceptance Criteria:
  - Control plane components can statically register metrics endpoints
  - Single aggregated metrics endpoint exists on data plane
  - Endpoint is protected via Kubernetes RBAC
  - Metrics propagation works reliably for clusters with no worker nodes
  - Documentation for registering new metrics endpoints