Improved login page

lib/utils/ui_utils.dart

@@ -2,12 +2,18 @@ import 'package:flutter/material.dart';
 
 /// User interface utilities
 
+/// Build centered progress bar
+Widget buildCenteredProgressBar() {
+  return Center(
+    child: CircularProgressIndicator(),
+  );
+}
+
+
 /// Build and return a full loading page
 Widget buildLoadingPage() {
   return Scaffold(
-    body: Center(
-      child: CircularProgressIndicator(),
-    ),
+    body: buildCenteredProgressBar(),
   );
 }