Migrate examples back, change to monorepo (#701)

examples/lib/stories/parallax/advanced.dart

@@ -0,0 +1,31 @@
+import 'package:flame/components.dart';
+import 'package:flame/parallax.dart';
+import 'package:flame/game.dart';
+
+class AdvancedParallaxGame extends BaseGame {
+  final _layersMeta = {
+    'parallax/bg.png': 1.0,
+    'parallax/mountain-far.png': 1.5,
+    'parallax/mountains.png': 2.3,
+    'parallax/trees.png': 3.8,
+    'parallax/foreground-trees.png': 6.6,
+  };
+
+  @override
+  Future<void> onLoad() async {
+    final layers = _layersMeta.entries.map(
+      (e) => loadParallaxLayer(
+        e.key,
+        velocityMultiplier: Vector2(e.value, 1.0),
+      ),
+    );
+    final parallax = ParallaxComponent.fromParallax(
+      Parallax(
+        await Future.wait(layers),
+        size,
+        baseVelocity: Vector2(20, 0),
+      ),
+    );
+    add(parallax);
+  }
+}