Provide more granular access to the federation endpoint

Currently, access to the federation endpoint requires a bearer token with `get` permission on the namespaces resource [1]

This grants more permissions than customer would like to grant by giving access to the federation endpoint. 

Does the move to kube rbac proxy facilate this in the future? 
This is not a request for namespace based access - but less expansive permissions than`get` on all namespaces 

 
[1]- https://docs.openshift.com/container-platform/4.14/monitoring/accessing-third-party-monitoring-apis.html#monitoring-querying-metrics-by-using-the-federation-endpoint-for-prometheus_accessing-third-party-monitoring-apis