[📑 Docs]: Normalize structure: GitLab CI with Testcontainers & LocalStack

[blkgrlcto]

What docs changes are you proposing?

Source: https://docs.localstack.cloud/aws/tutorials/gitlab-ci-testcontainers/

What’s missing

• Intro
• Prerequisites
• Architecture diagram
• Steps
• Testing the application (missing explicit section)
• Conclusion

Proposed edits

• Add ## Testing the application with reproducible commands and GitLab pipeline screenshot.

Acceptance criteria

• Clear Testing the application section with reproducible validation.

Code of Conduct

• I agree to follow this project's Code of Conduct

[anikchand461]

Hi @blkgrlcto , I'd like to take this on for Hacktoberfest! I'll focus on completing prerequisites and adding the Testing section.