Add `Project` page to website

[matthewpereira]

The OpenSSF best practices for open source projects recommends:

The project website MUST provide information on how to: obtain, provide feedback (as bug reports or enhancements), and contribute to the software. [interact]

We could add this to a Project page in the top level navigation of the openfga.dev website, which contains the following sorts of information:

1. Where is everything? - annotated list of repos (openfga, rfcs, website/docs, etc), Discord link
2. Why make OpenFGA - explain the project genesis and place in the tech landscape
3. How can I help? - link to contributors guide, discussions, discord, and guidance on how to give feedback
4. Report a security issue - link to GH security policy page and info on how to report
5. Thanks! - might be nice to mention Auth0, Okta, Auth0 Labs and the OCTO team, and key design partners/companies that have helped along the way