feat: create the main export file. exposes an instanc() method that w…

…hen called returns an instance

usage would be like  import RServer from 'R-Server'; let app = RServer.instance(configPath?);
app.listen(port?); app.get('/hello-world', (req, res) => res.end('Hello World'));

src/main.js

@@ -0,0 +1,10 @@
+import RServerApp from './modules/RServerApp.js';
+export default {
+
+    /**
+     * returns an app instance
+    */
+    instance(configPath) {
+        return new RServerApp(configPath);
+    }
+};