Flatpack example for shipping a binary package

Signed-off-by: Mitja Horvat <pinkfluid@gmail.com>

com.example.HelloWorld.yml

@@ -0,0 +1,18 @@
+app-id: com.example.HelloWorld
+runtime: org.freedesktop.Platform
+runtime-version: '23.08'
+sdk: org.freedesktop.Sdk
+command: hello
+finish-args:
+  - --share=ipc
+  - --socket=fallback-x11
+  - --socket=wayland
+modules:
+  - name: hello
+    buildsystem: simple
+    build-commands:
+      - gcc -o hello hello.c
+      - install -D hello /app/bin/hello
+    sources:
+      - type: file
+        path: hello.c