Add docs page for Create Next App (#15454)

Following up from #14830, this PR adds a new page to the docs for Create Next App. The content is identical to the README created as part of #14830. 

Also added a link on the main `getting-started` page to the new docs for Create Next App to help users find more info on Create Next App if needed. 

I'm unsure as to whether the content for the documentation needs to be different from the one I wrote for the README. Please let me know if that's the case, and I will be happy to tweak the structure.

docs/create-next-app.md

@@ -0,0 +1,55 @@
+---
+description: Create Next.js apps in one command with create-next-app.
+---
+
+# Create Next App
+
+The easiest way to get started with Next.js is by using `create-next-app`. This simple CLI tool enables you to quickly start building a new Next.js application, with everything set up for you. You can create a new app using the default Next.js template, or by using one of the [official Next.js examples](https://github.com/vercel/next.js/tree/canary/examples). To get started, use the following command:
+
+```bash
+npx create-next-app
+# or
+yarn create next-app
+```
+
+### Options
+
+`create-next-app` comes with the following options:
+
+- **-e, --example [name]|[github-url]** - An example to bootstrap the app with. You can use an example name from the [Next.js repo](https://github.com/vercel/next.js/tree/master/examples) or a GitHub URL. The URL can use any branch and/or subdirectory.
+- **--example-path [path-to-example]** - In a rare case, your GitHub URL might contain a branch name with a slash (e.g. bug/fix-1) and the path to the example (e.g. foo/bar). In this case, you must specify the path to the example separately: `--example-path foo/bar`
+
+### Why use Create Next App?
+
+`create-next-app` allows you to create a new Next.js app within seconds. It is officially maintained by the creators of Next.js, and includes a number of benefits:
+
+- **Interactive Experience**: Running `npx create-next-app` (with no arguments) launches an interactive experience that guides you through setting up a project.
+- **Zero Dependencies**: Initializing a project is as quick as one second. Create Next App has zero dependencies.
+- **Offline Support**: Create Next App will automatically detect if you're offline and bootstrap your project using your local package cache.
+- **Support for Examples**: Create Next App can bootstrap your application using an example from the Next.js examples collection (e.g. `npx create-next-app --example api-routes`).
+- **Tested**: The package is part of the Next.js monorepo and tested using the same integration test suite as Next.js itself, ensuring it works as expected with every release.
+
+## Related
+
+For more information on what to do next, we recommend the following sections:
+
+<div class="card">
+  <a href="/docs/basic-features/pages.md">
+    <b>Pages:</b>
+    <small>Learn more about what pages are in Next.js.</small>
+  </a>
+</div>
+
+<div class="card">
+  <a href="/docs/basic-features/built-in-css-support.md">
+    <b>CSS Support:</b>
+    <small>Use the built-in CSS support to add custom styles to your app.</small>
+  </a>
+</div>
+
+<div class="card">
+  <a href="/docs/api-reference/cli.md">
+    <b>CLI:</b>
+    <small>Learn more about the Next.js CLI.</small>
+  </a>
+</div>

docs/getting-started.md

@@ -29,6 +29,8 @@ yarn create next-app
 
 After the installation is complete, follow the instructions to start the development server. Try editing `pages/index.js` and see the result on your browser.
 
+For more information on how to use `create-next-app`, you can review the [`create-next-app` documentation](/docs/create-next-app.md)
+
 ## Manual Setup
 
 Install `next`, `react` and `react-dom` in your project: