Update README and CONTRIBUTING files to better inform how to contribute to this repo

The README file is the first document anyone see when viewing this repo. However, it lacks any reference to contributing to this repo. Without it people will not necessarily know how to proceed.

Additionally, the CONTRIBUTING file simply states what to do from a high level perspective. But there are no links to the documents and repos mentioned. This forces everyone to reach out to the repo's maintainers for information on every resource that is required.

These two documents should be edited to give prospective contributors more tools to get started with contributing on their own BEFORE first reaching out for these fundamental resources.

Specifically, the CONTRIBUTING file should point the contributor to THE "entry point" documentation required to get their workspace set up to start working on issues.
At the moment, it does not say to go to this README file to install certain softwares, files, repos, etc.
Note, the same info can be found here in the Learns App. But the first need access to that, which is also not mentioned in the CONTRIBUTING file.

Start with README.md and CONTRIBUTING.md in this repository, then review the linked node-homework README and Learns App setup lesson. Add contribution guidance to the README and link contributors to the workspace setup entry point and required resources in CONTRIBUTING.md. Done means prospective contributors can find the setup information without first contacting maintainers.