feat(modeling): increase default group size

lib/features/modeling/ElementFactory.js

@@ -188,7 +188,7 @@ ElementFactory.prototype._getDefaultSize = function(semantic) {
   }
 
   if (is(semantic, 'bpmn:Group')) {
-    return { width: 150, height: 120 };
+    return { width: 300, height: 300 };
   }
 
   return { width: 100, height: 80 };