* changed to new sidebar across projects except resources
* finalize multi sidebar support
* clean up
* remove redundant property
* small changes
* fixes
* generate
* fix error
* fix initial open
- Add a new homepage to `book` project for the routing page
- Move all main doc pages to be under `/v2/learn` (and added redirects + fixed links across docs)
- Other: add admin components to resources dropdown + fixes to search on mobile.
Closes DX-955
Preview: https://docs-v2-git-docs-router-page-medusajs.vercel.app/v2
- Documented common admin components with design that matches the admin.
- Updated existing admin customization snippets to match the admin's design.
Closes DOCS-964
