Create new top-level DefaultNodeInstance concept that will soon hold the "connection draining" logic

src/Microsoft.AspNetCore.NodeServices/Configuration/NodeServicesOptions.cs

@@ -0,0 +1,23 @@
+using System;
+using Microsoft.AspNetCore.NodeServices.HostingModels;
+
+namespace Microsoft.AspNetCore.NodeServices
+{
+    public class NodeServicesOptions
+    {
+        public const NodeHostingModel DefaultNodeHostingModel = NodeHostingModel.Http;
+
+        private static readonly string[] DefaultWatchFileExtensions = { ".js", ".jsx", ".ts", ".tsx", ".json", ".html" };
+
+        public NodeServicesOptions()
+        {
+            HostingModel = DefaultNodeHostingModel;
+            WatchFileExtensions = (string[])DefaultWatchFileExtensions.Clone();
+        }
+
+        public NodeHostingModel HostingModel { get; set; }
+        public Func<INodeInstance> NodeInstanceFactory { get; set; }
+        public string ProjectPath { get; set; }
+        public string[] WatchFileExtensions { get; set; }
+    }
+}