Add joafri image metadata in compose and multi-arch build/push script

Apps/_template/docker-compose.yaml

@@ -1,8 +1,12 @@
 name: sample-app
 
+x-image:
+  namespace: ${IMAGE_NAMESPACE:-joafri}
+  tag: ${IMAGE_TAG:-main}
+
 services:
   app:
-    image: ghcr.io/example/sample-app:1.0.0
+    image: ${IMAGE_NAMESPACE:-joafri}/sample-app-app:${IMAGE_TAG:-main}
     container_name: sample-app
     restart: unless-stopped