Re-organize documentation top-level navigation #411
Description
It's getting a bit busy with the new tutorial link. How can we simplify and make navigating our docs more intuitive?
See: #393 (comment)
I feel we should follow this work up with some re-organization inspired by a documentation model like diataxis or 7 action. E.g. a single "Getting started" top-nav element can include the installation instructions and the getting started tutorial (and other future tutorials, perhaps domain-specific). A single "APIs" top-level element can include our Python APIs and future R APIs. A single top-level "Contributing" element can include the development install guide, code quality and naming convention guides, a releasing guide, an architecture diagram, and more.