Unify examples structure (#1118)

* Animations, CameraAndViewport, CollisionDetection and Components unified

* Added descriptions to effects

* Rename input games

* Unify input stories

* Add info to parallax section

* Added descriptions to the rendering examples

* Add descriptions to the sprites directory

* Fix utils and rendering section

* Add descriptions to the widgets section

* Delete directory that rebase brought back

* Unify game names

* Added some styleguide docs for examples

* Fix analyze issues

* All files should have _example as suffix

* Made the FollowComponentExample a bit easier to understand

* Change priority of ember

examples/lib/stories/components/composability_example.dart

@@ -0,0 +1,72 @@
+import 'package:flame/components.dart';
+import 'package:flame/game.dart';
+import 'package:flame/input.dart';
+
+// This class only has `HasDraggables` since the game-in-game example moves a
+// draggable component to this game.
+class ComposabilityExample extends FlameGame with HasDraggables {
+  static const String description = '''
+    In this example we showcase how you can add children to a component and how
+    they transform together with their parent, if the parent is a
+    `PositionComponent`. This example is not interactive.
+  ''';
+
+  late ParentSquare parentSquare;
+
+  @override
+  bool debugMode = true;
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+    parentSquare = ParentSquare(Vector2.all(200), Vector2.all(300))
+      ..anchor = Anchor.center;
+    add(parentSquare);
+  }
+
+  @override
+  void update(double dt) {
+    super.update(dt);
+    parentSquare.angle += dt;
+  }
+}
+
+class ParentSquare extends RectangleComponent with HasGameRef {
+  ParentSquare(Vector2 position, Vector2 size)
+      : super(position: position, size: size);
+
+  @override
+  Future<void> onLoad() async {
+    super.onLoad();
+    createChildren();
+  }
+
+  void createChildren() {
+    // All positions here are in relation to the parent's position
+    const childSize = 50.0;
+    final children = [
+      RectangleComponent.square(
+        position: Vector2(100, 100),
+        size: childSize,
+        angle: 2,
+      ),
+      RectangleComponent.square(
+        position: Vector2(160, 100),
+        size: childSize,
+        angle: 3,
+      ),
+      RectangleComponent.square(
+        position: Vector2(170, 150),
+        size: childSize,
+        angle: 4,
+      ),
+      RectangleComponent.square(
+        position: Vector2(70, 200),
+        size: childSize,
+        angle: 5,
+      ),
+    ];
+
+    addAll(children);
+  }
+}