Pull pod/container labels from Prometheus

[laurivosandi]

If Prometheus is configured to work in conjunciton with kube-state-metrics there is kube_pod_labels info metric present which has all the Kubernetes pod labels attached and has historic data about it.

Sample:

kube_pod_labels{
container="kube-state-metrics
endpoint="http-metrics",
instance="10.244.157.32:8080",
job="kube-state-metrics",
label_app="mongodb-svc",
label_controller_revision_hash="mongodb-587956fc",
label_statefulset_kubernetes_io_pod_name="mongodb-0",
namespace="camtiler",
pod="mongodb-0",
service="kube-state-metrics",
uid="25a95958-7c7e-44ab-bab6-3a1723d7c51b"}

There is no need to record any of these labels in Logmower datastore and I believe we basically only need database index for pod UID