Add support for apb catalog relist

[dymurray]

Includes small error check for current-context gathering.

Note: I would like to come back to this to use the dynamic go client to grab these resources but this is clean for now.

[dymurray]

Fixes #56

[djwhatle]

@dymurray what do I need to do to make this work? I tried this:

$ apb catalog relist
WARN Failed to create a InternalClientSet: unable to load in-cluster configuration, KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT must be defined. 
ERRO Failed to get relist response. Expected status 200, got: 403 

[djwhatle]

Added more detailed error messages and suggested actions:

relist attempt without a bearer token

[dwhatley@precision-t apb]$ oc login -u system:admin
Logged into [...] as "system:admin" using existing credentials.
[...]
Using project "default".
[dwhatley@precision-t apb]$ apb catalog relist
ERRO Bearer token not found for current 'oc' user. Log in as a different user and retry. 
INFO View your current token with 'oc whoami -t'  
INFO Some users don't have a token, including 'system:admin' 

relist attempt without privileges to view routes

[dwhatley@precision-t apb]$ apb catalog relist
ERRO Bad relist response. Expected status 200, got: 403
{"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"clusterservicebrokers.servicecatalog.k8s.io \"openshift-automation-service-broker\" is forbidden: User \"apb-user\" cannot get clusterservicebrokers.servicecatalog.k8s.io at the cluster scope: User \"apb-user\" cannot get clusterservicebrokers.servicecatalog.k8s.io at the cluster scope","reason":"Forbidden","details":{"name":"openshift-automation-service-broker","group":"servicecatalog.k8s.io","kind":"clusterservicebrokers"},"code":403}
 
ERRO Current 'oc' user unable to get 'clusterservicebrokers'. Try again with a more privileged user.
 
INFO Administrators can grant 'cluster-admin' privileges with: 
INFO 'oc adm policy add-cluster-role-to-user cluster-admin <oc-user>' 

[djwhatle]

@dymurray in catasb env I found that I was unable to relist without manually specifying the name of my broker, which is expected, but we should put a PR into catasb to fix this (change ansible-service-broker to openshift-ansible-service-broker).

[djwhatle]

Not really related to your PR, but the long summary here feels overly detailed to be in the bare apb command help-text. Think we should consider stripping this down to just the short version.

[djwhatle]

Will be good to get this ported over to client-go so that we don't need a bearer token in the future, but works well enough for now since it's equivalent to previous tool.

$ apb catalog relist --name ansible-service-broker
Successfully relisted OpenShift Service Catalog for [ansible-service-broker]