RBAC with config file from Rancher fails

[rancher-max]

Describe the bug
Using a Kubeconfig file for a GKE cluster from Rancher and adding impersonation headers to it for RBAC causes failure when running rio commands: FATA[0000] {"Code":{"Code":"Forbidden","Status":403},"Message":"clusters.management.cattle.io \"c-ghd74\" is forbidden: User \"rio-admin\" cannot get resource \"clusters\" in API group \"management.cattle.io\" at the cluster scope","Cause":null,"FieldName":""} (get rioinfos.admin.rio.cattle.io rio)

To Reproduce

1. Use Rancher to create a GKE cluster
2. After the cluster has been provisioned, save the KUBECONFIG file locally. Update the users.user section to also have:

    as: rio-admin
    as-groups:
    - rio:admin

3. Run rio info or any rio command that reaches out to the cluster. It will fail

Expected behavior
Proxy the impersonation header through so as to have RBAC in rio.

Kubernetes version & type (GKE, on-prem): kubectl version

Client Version: version.Info{Major:"1", Minor:"16", GitVersion:"v1.16.0", GitCommit:"2bd9643cee5b3b3a5ecbd3af49d09018f0773c77", GitTreeState:"clean", BuildDate:"2019-09-19T13:57:45Z", GoVersion:"go1.12.9", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"14+", GitVersion:"v1.14.7-gke.10", GitCommit:"8cea5f8ae165065f0d35e5de5dfa2f73617f02d1", GitTreeState:"clean", BuildDate:"2019-10-05T00:08:10Z", GoVersion:"go1.12.9b4", Compiler:"gc", Platform:"linux/amd64"}

Type:
Rio version: rio info

Rio Version: v0.6.0-alpha.1 (7678d67d)
Rio CLI Version: v0.6.0-alpha.1 (7678d67d)

[rancher-max]

This issue still applies as Cluster Owner and with an RKE cluster, on rio v0.6.0-alpha.2

[izaac]

This issue still applies for rio v0.6.0-alpha.4 k3s v0.10.2 using a kubeconfig file generated by Rancher 2.3.2 @StrongMonkey

#623

[davidnuzik]

Depends on completion of #878