- K8s 1.14 introduced the pod and container labels and deprecated the
pod_name and container_name labels. K8s 1.16 removes the pod_name and
container_name labels.

- Metrics from K8s versions before 1.14 contain pod_name and
container_name labels. Metrics from K8s 1.14/1.15 contain pod, pod_name,
container and container_name labels. Metrics from K8s 1.16 onwards
contain pod and container labels.

- According to our docs, we need to support K8s 1.12 to 1.16.

- This commit changes existing queries to use pod instead of pod_name
and container instead of container_name. These changed queries should
work on K8s 1.14 onwards.

- This commit also adds a second query using `OR`. The second query
uses pod_name instead of pod, and container_name instead of container.
This second query should work on K8s 1.12 to 1.15.