ReactJS app moved to different folder

ReactJS app is moved to reactjs/dotnet-comment-app. Removed
project.lock.json file from source control.

samples/features/json/reactjs/dotnet-comments-app/Program.cs

@@ -0,0 +1,21 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using System.IO;
+
+namespace ReactCommentsApp
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            var host = new WebHostBuilder()
+                .UseKestrel()
+                .UseContentRoot(Directory.GetCurrentDirectory())
+                .UseIISIntegration()
+                .UseStartup<Startup>()
+                .Build();
+
+            host.Run();
+        }
+    }
+}