feat: Documentation and API reference (#348)

Co-authored-by: Vadim Smirnov <smirnou.vadzim@gmail.com>
Co-authored-by: zakariasaad <zakaria.elas@gmail.com>
Co-authored-by: Vilfred Sikker <vilfredsikker@gmail.com>
Co-authored-by: Kasper <kasper@medusa-commerce.com>
Co-authored-by: Sebastian Rindom <skrindom@gmail.com>
Co-authored-by: Kasper Fabricius Kristensen <45367945+kasperkristensen@users.noreply.github.com>

www/docs/sidebars.js

@@ -0,0 +1,77 @@
+/**
+ * Creating a sidebar enables you to:
+ - create an ordered group of docs
+ - render a sidebar for each doc of that group
+ - provide next/previous navigation
+
+ The sidebars can be generated from the filesystem, or explicitly defined here.
+
+ Create as many sidebars as you want.
+ */
+
+module.exports = {
+  tutorialSidebar: [
+    {
+      type: "doc",
+      id: "quickstart/quick-start",
+      label: "Quickstart",
+    },
+    // {
+    //   type: 'category',
+    //   label: 'Quickstart',
+    //   items: [
+    //     {
+    //       type: 'doc',
+    //       id: 'quickstart/quick-start-docker',
+    //       label: 'Quickstart w. Docker (Coming soon!)',
+    //     },
+    //   ],
+    // },
+    {
+      type: "category",
+      label: "Tutorials",
+      items: [
+        {
+          type: "doc",
+          id: "tutorial/set-up-your-development-environment",
+        },
+        {
+          type: "doc",
+          id: "tutorial/creating-your-medusa-server",
+        },
+        {
+          type: "doc",
+          id: "tutorial/adding-custom-functionality",
+        },
+        {
+          type: "doc",
+          id: "tutorial/linking-your-local-project-with-medusa-cloud",
+        },
+      ],
+    },
+    {
+      type: "category",
+      label: "How to",
+      items: [
+        {
+          type: "doc",
+          id: "how-to/plugins",
+        },
+        {
+          type: "doc",
+          id: "how-to/notification-api",
+        },
+        {
+          type: "category",
+          label: "Gatsby + Contentful + Medusa",
+          items: [
+            {
+              type: "doc",
+              id: "how-to/headless-ecommerce-store-with-gatsby-contentful-medusa",
+            },
+          ],
+        },
+      ],
+    },
+  ],
+}