Added base template for config ui.

appengine/config_service/ui/bower_components/polymer/externs/polymer-externs.js

+/**
+ * @fileoverview Externs for Polymer
+ * @externs
+ */
+
+/**
+ * @param {!{is: string}} init
+ * @return {!HTMLElement}
+ */
+function Polymer(init){}
+
+/**
+ * @param {string} string
+ * @param {Object} obj
+ * @return {string}
+ */
+function JSCompiler_renameProperty(string, obj) {}