Add keyword for getting all k8s objects (based on available api-resources) in a namespace

[Nilsty]

This keyword should list all objects in a namesapce by listing all available api-resources and then checking if this namespace has any resources of that type.

with kubectl this can be done via

kubectl api-resources --verbs=list --namespaced -o name \
  | xargs -n 1 kubectl get --show-kind --ignore-not-found -n default

This keyword can be used to validate the existence of k8s objects for a certain namespace.

I believe it would be nice to have the keyword return a json object like this:

{
  {
    "configmaps": [
      "cm_name1",
      "cm_name2",
      "cm_name3"
    ]
  },
    {
    "pods": [
      "pod_name1",
      "pod_name2",
      "pod_name3"
    ]
  }
}