implemented new loadable state concept

lib/state/app/infrastructure/loadableState/view/loadable_state_background_loading.dart

@@ -0,0 +1,21 @@
+import 'package:flutter/material.dart';
+
+class LoadableStateBackgroundLoading extends StatelessWidget {
+  final bool visible;
+  const LoadableStateBackgroundLoading({required this.visible, super.key});
+
+  final Duration animationDuration = const Duration(milliseconds: 200);
+
+  @override
+  Widget build(BuildContext context) => AnimatedSwitcher(
+      duration: animationDuration,
+      transitionBuilder: (Widget child, Animation<double> animation) => SlideTransition(
+        position: Tween<Offset>(
+          begin: const Offset(0.0, -1.0),
+          end: Offset.zero,
+        ).animate(animation),
+        child: child,
+      ),
+      child: visible ? const LinearProgressIndicator() : const SizedBox.shrink(),
+    );
+}