Add etch_a_sketch from https://github.com/SimplyMinimal/FlipperZero-Etch-A-Sketch

git-subtree-dir: etch_a_sketch
git-subtree-mainline: 8ae2535e9f113794146d493fb8573b61e259fe5b
git-subtree-split: 905c5f8ab60eaa33ae346513f801bd1b095bf7c9

etch_a_sketch/.gitsubtree

@@ -0,0 +1 @@
+https://github.com/SimplyMinimal/FlipperZero-Etch-A-Sketch main etch-a-sketch

etch_a_sketch/application.fam

@@ -0,0 +1,12 @@
+App(
+    appid="etch",
+    name="Etch A Sketch",
+    apptype=FlipperAppType.EXTERNAL,
+    entry_point="etch_a_sketch_app",
+    cdefines=["APP_ETCH_A_SKETCH"],
+    requires=["gui"],
+    stack_size=2 * 1024,
+    order=175,
+    fap_icon="etch-a-sketch-icon.png",
+    fap_category="Misc",
+)