docs: highlight and add details to Getting involved page

[hajjimo]

Creating this issue based on feedback from Don of Fynbos.

The Getting involved page is currently under Resources and should be placed higher in the navigation. Don suggested making it a top-level item or under Overview. Each section of the page should have more detailed steps where applicable. For example, instead of just linking to the repo in the contributing code section, provide a step-by-step list to help users find good first issues to contribute to.