Neat project!

I wanted to make some changes and thought I'd submit them to you in a PR, totally understand if you're not interested in them though - if that's the case feel free to close the PR.

• Feat: Add Dockerfile for container builds.
• Feat: Add Docker Compose example.
• Feat: Add optional authentication to the optillm proxy.
• Feat: Add the option of configuring optillm via environment variables.
• Feat: Add basic /health endpoint.
• Docs: Add documentation for running with Docker.
• Docs: Add documentation for args.
• Fix: Clean up mix of - and _ in args, handle old _ args for backwards compatibility.
• Fix: Minor linting in readme.
• Chore: Move arg parsing out of main to it's own class.