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/priority_example.dart

@@ -0,0 +1,42 @@
+import 'package:flame/components.dart';
+import 'package:flame/extensions.dart';
+import 'package:flame/game.dart';
+import 'package:flame/input.dart';
+
+class PriorityExample extends FlameGame with HasTappables {
+  static const String description = '''
+    On this example, click on the square to bring them to the front by changing
+    the priority.
+  ''';
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+    final squares = [
+      Square(Vector2(100, 100)),
+      Square(Vector2(160, 100)),
+      Square(Vector2(170, 150)),
+      Square(Vector2(110, 150)),
+    ];
+    addAll(squares);
+  }
+}
+
+class Square extends RectangleComponent
+    with HasGameRef<PriorityExample>, Tappable {
+  Square(Vector2 position)
+      : super(
+          position: position,
+          size: Vector2.all(100),
+          paint: PaintExtension.random(withAlpha: 0.9, base: 100),
+        );
+
+  @override
+  bool onTapDown(TapDownInfo info) {
+    final topComponent = gameRef.children.last;
+    if (topComponent != this) {
+      gameRef.children.changePriority(this, topComponent.priority + 1);
+    }
+    return false;
+  }
+}