docs: add page level sidebar (#1749)

* POC: docs: add page level sidebar

Closes #1341

* docs: hide level 1 test page from navbar

docs/sidebars.js

@@ -11,10 +11,25 @@
 
 // @ts-check
 
+const backToHomeLink = {
+  /** @type {"ref"} */
+  type: "ref",
+  id: "homepage",
+  label: "Back to home",
+  className: "menu__list-item--home",
+  customProps: {
+    icon: "TbArrowBackUp",
+    iconSize: 20,
+  },
+};
+
 /** @type {import('@docusaurus/plugin-content-docs').SidebarsConfig} */
 const sidebars = {
-  docsSidebar: [{type: 'autogenerated', dirName: '.'}],
-  // userGuideSidebar: [{type: 'autogenerated', dirName: 'user-guide'}]
+  docsSidebar: [{ type: "autogenerated", dirName: "." }],
+  level2PageSidebar: [
+    backToHomeLink,
+    { type: "autogenerated", dirName: "level-1/level-2" },
+  ],
 };
 
 module.exports = sidebars;