initial commit for "terraform show -json-redacted"

[jweigand]

This adds a new flag -json-redacted to terraform show. This mimics the output of terraform show -json but redacts sensitive values. Historically, showing those sensitive values made sense when the assumption was that it was being executed in a machine readable context, but this becomes significantly more dangerous when being executed in an agentic context - hence this new flag.

Fixes #

Target Release

1.16.x

Rollback Plan

• If a change needs to be reverted, we will roll out an update to the code within 7 days.

Changes to Security Controls

Are there any changes to security controls (access controls, encryption, logging) in this pull request? If so, explain.

CHANGELOG entry

• This change is user-facing and I added a changelog entry.
• This change is not user-facing.