Docs: Split Getting Started between App and Pages, improve `Installation` page (#72178)
Prepare **Getting Started** Section for upcoming changes, and work on
the first page: `Installation`.
Closes:
-
https://linear.app/vercel/issue/DOC-3703/update-how-getting-started-is-handled-in-next-site
-
https://linear.app/vercel/issue/DOC-3694/page-how-to-set-up-a-new-nextjs-project-installation
- https://linear.app/vercel/issue/DOC-3707/create-subsection-for-plugins
- https://linear.app/vercel/issue/DOC-3709/eslint-plugin-api-reference
- https://linear.app/vercel/issue/DOC-3710/typescript-reference-page
### Key Changes:
- Duplicate Getting Started Section between App and Pages Router docs
- Since getting started will vary between the routers, each docs needs
to have their own Getting Started section
- Reorganize folder numbers
**Installation Page**:
- Split app and pages router specific information
- Rename "Installation" to "How to set up a Next.js application" for SEO
- Add setup instructions for **TypeScript**
- Add setup instructions for **ESLint**
- Add setup instructions for **Absolute Imports and Module Path
Aliases**
**Side effects from moving content around**:
- Create a subsection in API Reference called **Configuration**.
- Add ESLint Plugin page, and update it to follow template
- Add TypeScript page, and update it to follow template
- Remove the **Absolute Imports and Module Path Aliases** page, it's
small enough to live under the set up instructions.
---------
Co-authored-by: Rich Haines <hello@richardhaines.dev>