feat: add benchmarks against nextjs (#26)

benches/nextjs-app-router/src/app/page.tsx

@@ -0,0 +1,10 @@
+export default async function Home(): Promise<JSX.Element> {
+  const { data } = await mockServerSideAPI()
+  return <h1>The random number is: {data}</h1>
+}
+
+const mockServerSideAPI = async (): Promise<{ data: number }> => {
+  return {
+    data: Math.floor(Math.random() * 10),
+  }
+}