Add cAdvisor Metrics to Autopilot/Standard GKE Cluster

[AnnaHeigl]

Added cAdvisor to the Monitoring Block to be able to collect and view cAdvisor metrics in Cloud Monitoring.

Checklist

I applicable, I acknowledge that I have:

• Read the contributing guide
• Ran terraform fmt on all modified files
• Regenerated the relevant README.md files using tools/tfdoc.py
• Made sure all relevant tests pass

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[juliocc]

Thanks for your contribution, @AnnaHeigl

Can you sign the CLA and address the linting issues?