perf(client): comment out core-js imports\n\nas most people won't need them

Author: Awk34

Diff for: templates/app/client/app/polyfills.js

@@ -1,5 +1,7 @@
-import 'core-js/es6';
-import 'core-js/es7/reflect';
+// Enable certain polyfills depending on which browsers you need to support
+// import 'core-js/es6';
+// import 'core-js/es7/reflect';
+
 import 'zone.js/dist/zone';
 
 <%_ if(filters.ts) { -%>