Updates all libraries and some cleanup in the Rust part.

frontend/src/App.js

@@ -17,9 +17,6 @@ function App() {
   const [games, setGames] = useState([]);
   const [activeGamenightId, setActiveGamenightId] = useState(null);
 
-  const POST_HEADER = {'Content-Type': 'application/json'};
-  const AUTH_HEADER = {'Authorization': `Bearer ${user?.jwt}`};
-
   const handleLogin = (input) => {
     unpack_api_result(login(input), setFlashData)
       .then(result => {