K8s 1.16 breaks default monitoring dashboard

Summary

(Summarize the bug encountered concisely)

K8s has changed the pod_name and container_name labels to pod and container respectively in 1.16 (https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/CHANGELOG-1.16.md#removed-metrics).

Our default metrics dashboard, and the pod metrics dashboard uses the pod_name and container_name labels extensively.

Steps to reproduce

(How one can reproduce the issue - this is very important)

1. Make sure that your K8s cluster is using version 1.16 or later. On GKE you need to choose 1.16 for the master version when manually creating a cluster.
2. You also need to follow these steps before you can do deployments with K8s 1.16.
3. Check the default metrics dashboard (Operations > Metrics) in a project. All queries with container_name or pod_name will return no data.

Example Project

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What is the current bug behavior?

(What actually happens)

Charts do not populate with data when using K8s version 1.16 or later.

What is the expected correct behavior?

(What you should see instead)

Charts should populate with data.

Relevant logs and/or screenshots

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Output of checks

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Results of GitLab environment info

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Results of GitLab application Check

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Possible fixes

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