Migrate to Docusaurus V2 🐱‍🐉 (#412)

* Migrate to Docusaurus V2

* Add redirects

Only covers most recent version

* Add omitted scripts folder

* Include working yarn.lock

docusaurus.config.js

@@ -0,0 +1,74 @@
+module.exports = {
+  title: 'Home Assistant Developer Docs',
+  tagline: 'All you need to start developing for Home Assistant',
+  url: 'https://developers.home-assistant.io',
+  baseUrl: '/',
+  favicon: 'img/favicon.png',
+  organizationName: 'facebook', // Usually your GitHub org/user name.
+  projectName: 'docusaurus', // Usually your repo name.
+  themeConfig: {
+    googleAnalytics: {
+      trackingID: 'UA-57927901-3',
+    },
+    navbar: {
+      title: 'Developer Docs',
+      logo: {
+        alt: 'Home Assistant',
+        src: 'img/logo-pretty.svg',
+      },
+      links: [
+        {to: 'docs/architecture_index', label: 'Architecture', position: 'left'},
+        {to: 'docs/frontend_index', label: 'Frontend', position: 'left'},
+        {to: 'docs/development_index', label: 'Backend', position: 'left'},
+        {to: 'docs/misc', label: 'Misc', position: 'left'},
+        {to: 'blog', label: 'Blog', position: 'left'},
+      ],
+    },
+    footer: {
+      logo: {
+        alt: 'Home Assistant',
+        src: 'img/logo-white.svg',
+        href: 'https://www.home-assistant.io',
+      },
+      style: 'dark',
+      links: [
+        {
+          title: 'Social',
+          items: [
+            {
+              label: 'Blog',
+              to: 'blog',
+            },
+            {
+              label: 'GitHub',
+              href: 'https://github.com/home-assistant/developers.home-assistant',
+            },
+            {
+              label: 'Twitter',
+              href: 'https://twitter.com/hass_devs',
+            },
+          ],
+        },
+      ],
+      copyright: `Copyright © ${new Date().getFullYear()} Home Assistant, Inc. Built with Docusaurus.`,
+    },
+  },
+  presets: [
+    [
+      '@docusaurus/preset-classic',
+      {
+        docs: {
+          sidebarPath: require.resolve('./sidebars.js'),
+          editUrl:
+            'https://github.com/home-assistant/developers.home-assistant/edit/master/',
+        },
+        theme: {
+          customCss: require.resolve('./src/css/custom.css'),
+        },
+        blog: {
+          postsPerPage: 10,
+        },
+      },
+    ],
+  ],
+};