Export src/terraform/mlz output by default

[glennmusa]

Benefit/Result/Outcome
It would be helpful if the output from the main deployment was always available for reference.

Description
Today, the --write-output flag is an optional deployment setting. If I skipped this flag out of not-knowing it exists, when I go to deploy a Tier 3, the deployment will fail because the file could not be found.

The file is small and contains no secrets.

Acceptance Criteria

• Write the output by default
• Write the output with the environment name in the file name to keep consistency with how we generate .mlzconfig files and .tfvars files
• Write the output as .tfvars instead of json so that the tier3/main.tf maintains compatibility with user-supplied .tfvars files.
• Update the tier3/main.tf to remove the .value references
• Write to output silently -- today output is tee'd to a file, use redirect instead so that it doesn't appear in the stdout during apply

[glennmusa]

+@sstjean

[brooke-hamilton]

@glennmusa do we still need this issue or is it OBE when we remove the scripting layer?

[brooke-hamilton]

Closing because the scripting layer for Terraform will be removed.