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/sprites/basic_sprite_example.dart

@@ -0,0 +1,23 @@
+import 'package:flame/components.dart';
+import 'package:flame/game.dart';
+
+class BasicSpriteExample extends FlameGame {
+  static const String description = '''
+    In this example we load a sprite from the assets folder and put it into a
+    `SpriteComponent`.
+  ''';
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+    final sprite = await loadSprite('flame.png');
+    add(
+      SpriteComponent(
+        sprite: sprite,
+        position: size / 2,
+        size: sprite.srcSize * 2,
+        anchor: Anchor.center,
+      ),
+    );
+  }
+}