Add usimp.js

www/res/js/usimp.js

@@ -0,0 +1,9 @@
+"use strict";
+
+let usimp = {};
+
+usimp.lookup = function (domain_name) {
+    return fetch(`https://${domain_name}/.well-known/usimp.json`, {
+        redirect: "manual",
+    });
+}