Enhance deploy to output JSON instead of plain-english

[nadig-google]

NOTE NOTE NOTE
This a draft Pull Request to solicit early feedback. It has not been tested. This is also not the final implementation.
NOTE NOTE NOTE

This pull request adds support to output JSON instead of the usual "english text output" to "gcluster deploy". It adds a new flag to the deploy command called --json-output which writes a file called cluster_toolkit_output.json with the output messages written JSON format (instead of the usual "english text output" to STDOUT.

This pull request was submitted git commit --no-verify because of failing go staticchecks that prevent git commit from successfully running

What works as of now

• Writes output to JSON file
• Writes unique file per Terraform group to avoid files being overwritten

What does not work as of now:

• Cluster Deployment does not seem to work (I am unsure if the failure is related to my changes)
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  Related (older and deprecated) PR: Draft implementation to support JSON output #3604