Cache Component Guide: Building public, _mostly_ static pages (#87248)
This PR adds a draft guide for building public pages with Cache
Components and PPR.
Part of a 3-guide series on:
- Building public pages with shared data
- Building page variants with route params (`generateStaticParams`)
- Build private pages with user-specific data
Todo:
- [x] Link to glossary terms
- [x] Link to video
- [x] Link to demo + code