Move files to src and comply with the dart package layout convention (#621)

* 👌 Use `Offset` type directly in `JoystickAction.update` calculations (#631)

* Move files to src and comply with the dart package layout convention

* Fixing widgets example

Co-authored-by: Serge Matveenko <lig@countzero.co>
Co-authored-by: Erick Zanardo <erickzanardoo@gmail.com>

lib/src/components/sprite_component.dart

@@ -0,0 +1,46 @@
+import 'dart:ui';
+
+import 'package:flutter/foundation.dart';
+
+import '../extensions/vector2.dart';
+import '../sprite.dart';
+import 'component.dart';
+import 'position_component.dart';
+
+export '../sprite.dart';
+
+/// A [PositionComponent] that renders a single [Sprite] at the designated
+/// position, scaled to have the designated size and rotated to the specified
+/// angle.
+///
+/// This a commonly used subclass of [Component].
+class SpriteComponent extends PositionComponent {
+  /// The [sprite] to be rendered by this component.
+  Sprite sprite;
+
+  /// Use this to override the colour used (to apply tint or opacity).
+  ///
+  /// If not provided the default is full white (no tint).
+  Paint overridePaint;
+
+  /// Creates a component with an empty sprite which can be set later
+  SpriteComponent();
+
+  SpriteComponent.fromImage(Vector2 size, Image image)
+      : this.fromSprite(size, Sprite(image));
+
+  SpriteComponent.fromSprite(Vector2 size, this.sprite) {
+    super.size.setFrom(size);
+  }
+
+  @mustCallSuper
+  @override
+  void render(Canvas canvas) {
+    super.render(canvas);
+    sprite?.render(
+      canvas,
+      size: size,
+      overridePaint: overridePaint,
+    );
+  }
+}