Marketing improvements 3 (#3175)

* Improve marketing website

* User guide with icons

* Add TOC

* Linter

* Basic GraphQL playground

* Very basic contributors page

* Failed attempt to integrate REST playground

* Yarn

* Begin contributors DB

* Improve contributors page

packages/twenty-website/src/app/developers/page.tsx

@@ -0,0 +1,9 @@
+const Developers = () => {
+  return (
+    <div>
+      <p>This page should probably be built on Framer</p>
+    </div>
+  );
+};
+
+export default Developers;