Edit CONTRIBUTING.md

[suhacker1]

Is your feature request related to a problem? Please describe.
Instead of a list of bullet points, it would be nice to reorganize the file into sections. It would be helpful if more attention was paid to installation and setup.

Detail any additional context.
Make sure to include that:

• Right now, all of the tests run on GitHub Actions and therefore must explicitly be defined as not using a GPU
• All issues under "needs validation" (like this one) should have a comment with an overview of the solution on the issue itself
• Commands often need poetry to run like poetry run python or poetry run pytest
• It is best to run Nox before making any commits
• Explain how to look at the GitHub Projects. The most important issues are at the top
• Take a look at "help wanted" issues first
• We prefer tests using Python Hypothesis
• Link to relevant papers
• Code should adhere to PyTorch and PyTorch Lightning best practices (See: 1, 2, 3, 4, 5)
• We're interested in new issues that add new synthesizers, attack configurations, strategies, victim models, and substitute model architectures (or, broadly, whatever improves the scope, efficiency, and effectiveness of PrivacyRaven)
• Some papers are not reproducible