introduce CONTRIBUTING.md #8
Description
currently usage information and development information is intertwined in the README, making it more difficult to read through for a novice. introducing a CONTRIBUTING.md makes this a clear split. we can link to the CONTRIBUTING.md from the README.md to make sure it's not lost.
Also github recognized this file and will present it to users in via a quick menu action like README/LICENSE: https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/setting-guidelines-for-repository-contributors