Initial check-in for scenes demo.

plugins/scenes/application.fam

@@ -0,0 +1,10 @@
+App(
+    appid="Scenes_Demo",
+    name="Scenes Demo",
+    apptype=FlipperAppType.EXTERNAL,
+    entry_point="scenes_demo_app",
+    requires=["gui"],
+    stack_size=2 * 1024,
+    fap_icon="scenes_demo.png",
+    fap_category="Misc",
+)