Add contributing.md to repo

[chris-bateman]

I've been thinking about how we can make our contribution process smoother.

Why We Need a CONTRIBUTING.md

• Efficiency: With clear guidelines, we can reduce back-and-forth on PRs and issues. And reduce setup/troubleshooting time for getting started.

What to Include

Here's what I'm thinking we could cover in the CONTRIBUTING.md:

1. Quick Start Guide: How to fork, clone, and set up the project locally.
2. What We're Looking For: Types of helpful contributions (bug fixes, features, docs updates, etc.).
3. How to Submit Contributions: Steps for opening issues, creating PRs, etc.
4. Style Guide: Coding standards, naming conventions, etc.
5. PR Process: How we review and merge PRs, including any CI/CD stuff.

More info here - https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/setting-guidelines-for-repository-contributors

Next Steps

I'm happy to draft the initial version of this and get your feedback.