Adding API Endpoints for Catalog Items (#410)

* Adding new Endpoints

* update nuget packages

* Modifying API to work well with Swagger.

* Remove Swashbuckle.Core

src/Web/API/BaseResponse.cs

@@ -0,0 +1,19 @@
+using System;
+
+namespace Microsoft.eShopWeb.Web.API
+{
+    /// <summary>
+    /// Base class used by API responses
+    /// </summary>
+    public abstract class BaseResponse : BaseMessage
+    {
+        public BaseResponse(Guid correlationId) : base()
+        {
+            base._correlationId = correlationId;
+        }
+
+        public BaseResponse()
+        {
+        }
+    }
+}