docs(v2): add docs skeleton and structure (#1412)

* docs(v2): add docs skeleton and structure

* docs(v2): add on

* docs(v2): move motivation into contributing

website/sidebars.js

@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+module.exports = {
+  docs: {
+    'Getting Started': [
+      'introduction',
+      'installation',
+      'project-structure',
+      'deployment',
+    ],
+    Guides: [
+      'configuration',
+      'creating-pages',
+      'writing-documentation',
+      'assets',
+      'markdown',
+      'styling-layout',
+      'using-plugins',
+      'using-themes',
+      'search',
+      'analytics',
+    ],
+    'Advanced Guides': ['blog', 'plugins', 'themes', 'presets'],
+    'API Reference': [
+      'cli',
+      'docusaurus-core',
+      'docusaurus.config.js',
+      'plugins',
+    ],
+    Contributing: ['how-to-contribute', 'motivation', 'design-principles'],
+  },
+};