Refactored ScaleEffect to the new effects engine (#1123)

* Scale effect

* Scale effect should affect scale...

* Add ScaleEffect example

* Added `ScaleEffect`

* Fix analyze issue

* Fix ScaleEffect tests

examples/lib/stories/effects/old_scale_effect_example.dart

@@ -0,0 +1,48 @@
+import 'package:flame/components.dart';
+import 'package:flame/effects.dart';
+import 'package:flame/extensions.dart';
+import 'package:flame/game.dart';
+import 'package:flame/input.dart';
+import 'package:flame/palette.dart';
+import 'package:flutter/material.dart';
+
+import '../../commons/square_component.dart';
+
+class OldScaleEffectExample extends FlameGame with TapDetector {
+  static const String description = '''
+    The `ScaleEffect` scales up the canvas before drawing the components and its
+    children.
+    In this example you can tap the screen and the component will scale up or down,
+    depending on its current state.
+  ''';
+
+  late SquareComponent square;
+  bool grow = true;
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+    square = SquareComponent()
+      ..position.setValues(200, 200)
+      ..anchor = Anchor.center;
+    square.paint = BasicPalette.white.paint()..style = PaintingStyle.stroke;
+    final childSquare = SquareComponent(position: Vector2.all(70), size: 20);
+
+    square.add(childSquare);
+    add(square);
+  }
+
+  @override
+  void onTap() {
+    final s = grow ? 3.0 : 1.0;
+
+    grow = !grow;
+    square.add(
+      ScaleEffect(
+        scale: Vector2.all(s),
+        speed: 2.0,
+        curve: Curves.linear,
+      ),
+    );
+  }
+}