docs: restructured docs sidebar (#2156)

* restructured docs sidebar

* resolved incorrect URLs

www/docs/src/theme/DocSidebar/Desktop/index.js

@@ -0,0 +1,41 @@
+import React from 'react';
+import clsx from 'clsx';
+import {useThemeConfig} from '@docusaurus/theme-common';
+import Logo from '@theme/Logo';
+import CollapseButton from '@theme/DocSidebar/Desktop/CollapseButton';
+import Content from '@theme/DocSidebar/Desktop/Content';
+import styles from './styles.module.css';
+import DocSidebarItem from '@theme/DocSidebarItem';
+
+function DocSidebarDesktop({path, sidebar, onCollapse, isHidden}) {
+  const {
+    navbar: {hideOnScroll},
+    docs: {
+      sidebar: {hideable},
+    },
+    sidebarFooter = [],
+  } = useThemeConfig();
+
+  return (
+    <div
+      className={clsx(
+        styles.sidebar,
+        hideOnScroll && styles.sidebarWithHideableNavbar,
+        isHidden && styles.sidebarHidden,
+      )}>
+      {hideOnScroll && <Logo tabIndex={-1} className={styles.sidebarLogo} />}
+      <Content path={path} sidebar={sidebar} />
+      <ul className={
+        clsx(
+          styles.sidebarFooterList
+        )
+      }>
+        {sidebarFooter.map((item, index) => (
+          <DocSidebarItem key={index} item={item} index={index} level={1} />
+        ))}
+      </ul>
+      {hideable && <CollapseButton onClick={onCollapse} />}
+    </div>
+  );
+}
+export default React.memo(DocSidebarDesktop);