[Containment] Add general policy for containment rules

Add general policy for supporting containment rules, WTD-962.

platform/containment/src/CompositionPolicy.js

@@ -0,0 +1,29 @@
+/*global define*/
+
+define(
+    ['./ContainmentTable'],
+    function (ContainmentTable) {
+        "use strict";
+
+        /**
+         * Defines composition policy as driven by type metadata.
+         */
+        function CompositionPolicy(typeService, capabilityService) {
+            // We're really just wrapping the containment table and rephrasing
+            // it as a policy decision.
+            var table = new ContainmentTable(typeService, capabilityService);
+
+            return {
+                /**
+                 * Is the type identified by the candidate allowed to
+                 * contain the type described by the context?
+                 */
+                allow: function (candidate, context) {
+                    return table.canContain(candidate, context);
+                }
+            };
+        }
+
+        return CompositionPolicy;
+    }
+);