feat: npm init docusaurus, yarn create docusaurus (#5635)

* initial create-docusaurus impl

* cleanup

* @docusaurus/init renamed to create-docusaurus

* 0.0.6

* update lockfile

* fix lint

* remove npm2yarn for "npm init" because npm2yarn doesn't convert it and yarn result fails to execute

* prettier

* add correct version

* prettier

* prettier

* prettier

* prettier

* fix annoying --config .prettierrc issue

packages/create-docusaurus/templates/shared/docs/intro.md

@@ -0,0 +1,35 @@
+---
+sidebar_position: 1
+---
+
+# Tutorial Intro
+
+Let's discover **Docusaurus in less than 5 minutes**.
+
+## Getting Started
+
+Get started by **creating a new site**.
+
+Or **try Docusaurus immediately** with **[docusaurus.new](https://docusaurus.new)**.
+
+## Generate a new site
+
+Generate a new Docusaurus site using the **classic template**:
+
+```shell
+npm init docusaurus@latest my-website classic
+```
+
+## Start your site
+
+Run the development server:
+
+```shell
+cd my-website
+
+npx docusaurus start
+```
+
+Your site starts at `http://localhost:3000`.
+
+Open `docs/intro.md` and edit some lines: the site **reloads automatically** and display your changes.