* docs: changes to AI assistant icon + add button to code blocks
* fix code blocks in questions
* collapse code block in answer
* styling fixes
* fix new line at cursor position
- 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
