MAPG-180 extract all inline JS into separate JS file

public/static/js/login/google_signup.js

@@ -0,0 +1,21 @@
+(function () {
+    var form = document.getElementById('googleSignupForm');
+
+    form.onsubmit = function (e) {
+        document.getElementById('loading').style.visibility = 'visible';
+
+        e.preventDefault();
+
+        MapGuesser.httpRequest('POST', form.action, function () {
+            window.location.replace('/');
+        });
+    };
+
+    document.getElementById('cancelGoogleSignupButton').onclick = function () {
+        document.getElementById('loading').style.visibility = 'visible';
+
+        MapGuesser.httpRequest('POST', '/signup/google/reset', function () {
+            window.location.replace('/signup');
+        });
+    };
+})();