Make common_metrics dashboard work on K8s 1.12 to 1.16

What does this MR do?

• 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. Metrics from K8s 1.16 onwards contain pod and container labels.

• According to https://docs.gitlab.com/ee/user/project/clusters/#supported-cluster-versions, we need to support K8s 1.12 to 1.16.

• This MR 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 MR 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 for K8s 1.12 to 1.15.

Issue: #216022 (closed)

Screenshots

Using K8s 1.16:

Before	After

K8s 1.14	K8s 1.15

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team