add static site generation including robots.txt and sitemap.xml

frontend/src/api/requestFreeRooms.ts

@@ -19,6 +19,9 @@ export async function requestFreeRooms(
   from: string,
   to: string,
 ): Promise<string[]> {
+  if (import.meta.env.SSR) {
+    return [];
+  }
   const rooms: string[] = [];
   await fetch("/api/rooms/free?from=" + from + "&to=" + to)
     .then((response) => {