Major changes in this PR to how the About page is rendered.
Bringing back the static, serverside-generated About page from v3. This involved reverting a lot of code and modifying some of the variables names to match changes in v4.
Update the table of contents generator to also parse markdown
Change a bunch of in-app routing to redirect to the static About page instead of the React component route
Incorporate @ClearlyClaire's open PR for a setting that lets admins choose to make the explore page their non-logged-in landing page instead of About (but About is the default)
Major changes in this PR to how the About page is rendered.
Anyway, looking good: