* website: various updates
* Expose /docs and /intro views using documentation-style
layout for index pages
* Add [Use Case] Secrets Management page
* Add [Use Case] Data Encryption page
* Add [Use Case] Identity Based Access page
* Update redirects file removing `/intro` routes redirecting to
`learn.hashicorp`
* Hide MegaNav on mobile
* website: route /api straight to documentation
* Bybass index page and jump straight to content
