chore: Remove terratest workflow and correct documentation links

[bryantbiggs]

What does this PR do?

• Remove terratest workflow; we can re-evaluate in the future based on what our standardized testing strategy will be for patterns
• Correct broken links in documentation
• Update documentation to reflect changes in v5

Motivation

• Correct documentation and broken links
• Closes chore(deps): Bump github.com/prometheus/client_golang from 1.11.0 to 1.11.1 in /test/aws #1434
• Closes chore(deps): Bump github.com/prometheus/client_golang from 1.11.0 to 1.11.1 in /test #1435
• Closes Update getting-started.md #1436
• Closes Update getting-started.md #1437
• Closes chore(deps): Bump github.com/hashicorp/go-getter from 1.6.1 to 1.7.0 in /test #1440

More

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Yes, I have updated the docs for this feature
• Yes, I ran pre-commit run -a with this PR

For Moderators

• E2E Test successfully complete before merge?

Additional Notes