Create guidelines for contributing to Supernova

[seanprashad]

Prefixing commit messages and PR's with feat, doc etc will help maintainers to identify what a commit was intended to change.

Getting started on a CONTRIBUTING.md with proper guidelines to follow would be great!

We can take inspiration from Rust's own CONTRIBUTING.md, Rustfmt's CONTRIBUTING.md or Rust-Cookbook's CONTRIBUTING.md.

[0xazure]

I need to figure out where I picked up the message prefixes from, I think it would make a good addition to CONTRIBUTING.md and would help newcomers understand the reasoning behind it.

I'd also like to add How to Write a Git Commit Message as an additional resource for reference.

Definitely want to draw inspiration from existing CONTRIBUTING.mds, no sense in reinventing the wheel when there's so much goodness out there, and thanks for pulling together that list for inspiration!