Convert backend to ESM

- About 5 years overdue
- Remove eslint, use bomejs instead

backend/lib/express/jwt.js

@@ -1,13 +1,13 @@
-module.exports = function () {
-	return function (req, res, next) {
+export default function () {
+	return (req, res, next) => {
 		if (req.headers.authorization) {
-			let parts = req.headers.authorization.split(' ');
+			const parts = req.headers.authorization.split(" ");
 
-			if (parts && parts[0] === 'Bearer' && parts[1]) {
+			if (parts && parts[0] === "Bearer" && parts[1]) {
 				res.locals.token = parts[1];
 			}
 		}
 
 		next();
 	};
-};
+}