adding basic widget for device managment

lib/core/extension/build_context_x.dart

@@ -0,0 +1,17 @@
+import 'package:flutter/material.dart';
+
+extension BuildContextExt on BuildContext {
+  ThemeData get theme => Theme.of(this);
+
+  TextTheme get textTheme => Theme.of(this).textTheme;
+
+  AppBarTheme get appBarTheme => Theme.of(this).appBarTheme;
+
+  Size get screenSize => MediaQuery.of(this).size;
+
+  double get screenWidth => MediaQuery.of(this).size.width;
+
+  double get screenHeight => MediaQuery.of(this).size.height;
+
+  double get textScale => MediaQuery.textScalerOf(this).scale(1);
+}