WIP: New User Guide (#3984)

* initial commit

* Theme setup on twenty-website package

* Left bar, Content done

* Content added, useDeviceType hook added

* useDeviceType file renamed

* Responsiveness introduced

* Mobile responsiveness fix

* TOC layout

* PR fixes

* PR changes 2

* PR changes #3

packages/twenty-website/src/app/user-guide/page.tsx

@@ -0,0 +1,5 @@
+import UserGuideMain from '@/app/components/user-guide/UserGuideMain';
+
+export default async function UserGuideHome() {
+  return <UserGuideMain />;
+}