Added scaffolded Login page for Identity

- Also updated the _LoginPartial to use the new page

src/Web/Areas/Identity/IdentityHostingStartup.cs

@@ -0,0 +1,21 @@
+using System;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.AspNetCore.Identity.UI;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.eShopWeb.Infrastructure.Identity;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+
+[assembly: HostingStartup(typeof(Microsoft.eShopWeb.Web.Areas.Identity.IdentityHostingStartup))]
+namespace Microsoft.eShopWeb.Web.Areas.Identity
+{
+    public class IdentityHostingStartup : IHostingStartup
+    {
+        public void Configure(IWebHostBuilder builder)
+        {
+            builder.ConfigureServices((context, services) => {
+            });
+        }
+    }
+}