feat(contrib): git commit message generator

[Mustaballer]

What kind of change does this PR introduce?

Addresses #189. Adds CLI tool that uses OpenAI to generate git commit messages while executing in Docker environment.

Summary

Automatically generates git commit message based on code changes in files with git diff and git status

Checklist

• My code follows the style guidelines of OpenAdapt
• I have performed a self-review of my code
• If applicable, I have added tests to prove my fix is functional/effective
• I have linted my code locally prior to submission
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (e.g. README.md, requirements.txt)
• New and existing unit tests pass locally with my changes

How can your code be run and tested?

Run this command in root directory
python -m openadapt.contrib.git_message generate_git_commit_message [path/to/repo] # default to current directory

[cr-gpt]

Seems you are using me but didn't get OPENAI_API_KEY seted in Variables/Secrets for this repo. you could follow readme for more information