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/system/pause_resume_example.dart

@@ -0,0 +1,53 @@
+import 'package:flame/components.dart';
+import 'package:flame/game.dart';
+import 'package:flame/input.dart';
+
+class PauseResumeExample extends FlameGame with TapDetector, DoubleTapDetector {
+  static const description = '''
+    Demonstrate how to use the pause and resume engine methods and paused
+    attribute.
+
+    Tap on the screen to toggle the execution of the engine using the
+    `resumeEngine` and `pauseEngine`.
+
+    Double Tap on the screen to toggle the execution of the engine using the
+    `paused` attribute.
+  ''';
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+
+    final animation = await loadSpriteAnimation(
+      'animations/chopper.png',
+      SpriteAnimationData.sequenced(
+        amount: 4,
+        textureSize: Vector2.all(48),
+        stepTime: 0.15,
+      ),
+    );
+
+    add(
+      SpriteAnimationComponent(
+        animation: animation,
+      )
+        ..position = size / 2
+        ..anchor = Anchor.center
+        ..size = Vector2.all(100),
+    );
+  }
+
+  @override
+  void onTap() {
+    if (paused) {
+      resumeEngine();
+    } else {
+      pauseEngine();
+    }
+  }
+
+  @override
+  void onDoubleTap() {
+    paused = !paused;
+  }
+}