feat: implement feed and validation utilities for smartfeed

ts/plugins.ts

@@ -0,0 +1,10 @@
+// tsclass scope
+import * as tsclass from '@tsclass/tsclass';
+
+export { tsclass };
+
+// third party scope
+import rssParser from 'rss-parser';
+import * as feed from 'feed';
+
+export { rssParser, feed };