[Policy] Add example of usage

Add example showing usage of policy, WTD-973.

example/policy/bundle.json

@@ -0,0 +1,12 @@
+{
+    "name": "Example Policy",
+    "description": "Provides an example of using policies to prohibit actions.",
+    "extensions": {
+        "policies": [
+            {
+                "implementation": "ExamplePolicy.js",
+                "category": "action"
+            }
+        ]
+    }
+}

example/policy/src/ExamplePolicy.js

@@ -0,0 +1,26 @@
+/*global define*/
+
+define(
+    [],
+    function () {
+        "use strict";
+
+        function ExamplePolicy() {
+            return {
+                /**
+                 * Disallow the Remove action on objects whose name contains
+                 * "foo."
+                 */
+                allow: function (action, context) {
+                    var domainObject = (context || {}).domainObject,
+                        model = (domainObject && domainObject.getModel()) || {},
+                        name = model.name || "",
+                        metadata = action.getMetadata() || {};
+                    return metadata.key !== 'remove' || name.indexOf('foo') < 0;
+                }
+            };
+        }
+
+        return ExamplePolicy;
+    }
+);