Docusarus: Init Project (#1312)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1312

This starts us transitioning the Yoga website off of an ancient version of Gatsby by initializing a new Docusaurus project. This commit adds a new stock project, to be filled in later, then fixes license lint errors.

Note that this seems to have init'd using npm, but in the next diff I convert this to yarn workspaces anyway.

Reviewed By: yungsters

Differential Revision: D46884434

fbshipit-source-id: 7a0a4dddc144ad2d22cd18a02e8dcb9ff2184489

website-next/docs/intro.md

@@ -0,0 +1,47 @@
+---
+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)**.
+
+### What you'll need
+
+- [Node.js](https://nodejs.org/en/download/) version 16.14 or above:
+  - When installing Node.js, you are recommended to check all checkboxes related to dependencies.
+
+## Generate a new site
+
+Generate a new Docusaurus site using the **classic template**.
+
+The classic template will automatically be added to your project after you run the command:
+
+```bash
+npm init docusaurus@latest my-website classic
+```
+
+You can type this command into Command Prompt, Powershell, Terminal, or any other integrated terminal of your code editor.
+
+The command also installs all necessary dependencies you need to run Docusaurus.
+
+## Start your site
+
+Run the development server:
+
+```bash
+cd my-website
+npm run start
+```
+
+The `cd` command changes the directory you're working with. In order to work with your newly created Docusaurus site, you'll need to navigate the terminal there.
+
+The `npm run start` command builds your website locally and serves it through a development server, ready for you to view at http://localhost:3000/.
+
+Open `docs/intro.md` (this page) and edit some lines: the site **reloads automatically** and displays your changes.