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/components/ExternalArrow.tsx

@@ -0,0 +1,16 @@
+export const ExternalArrow = () => {
+  return (
+    <div style={{ width: '14px', height: '14px', fill: 'rgb(179, 179, 179)' }}>
+      <svg
+        xmlns="http://www.w3.org/2000/svg"
+        viewBox="0 0 256 256"
+        focusable="false"
+        color="rgb(179, 179, 179)"
+      >
+        <g color="rgb(179, 179, 179)">
+          <path d="M200,64V168a8,8,0,0,1-16,0V83.31L69.66,197.66a8,8,0,0,1-11.32-11.32L172.69,72H88a8,8,0,0,1,0-16H192A8,8,0,0,1,200,64Z"></path>
+        </g>
+      </svg>
+    </div>
+  );
+};