[Alarms & Timers] Add screenshots

apps/alarm/metadata.json

@@ -13,5 +13,18 @@
     { "name": "alarm.app.js", "url": "app.js" },
     { "name": "alarm.img", "url": "app-icon.js", "evaluate": true },
     { "name": "alarm.wid.js", "url": "widget.js" }
+  ],
+  "screenshots": [
+    { "url": "screenshot-1.png" },
+    { "url": "screenshot-2.png" },
+    { "url": "screenshot-3.png" },
+    { "url": "screenshot-4.png" },
+    { "url": "screenshot-5.png" },
+    { "url": "screenshot-6.png" },
+    { "url": "screenshot-7.png" },
+    { "url": "screenshot-8.png" },
+    { "url": "screenshot-9.png" },
+    { "url": "screenshot-10.png" },
+    { "url": "screenshot-11.png" }
   ]
 }