Adding 2FA Authenticator Support (#66)

* Adding support for 2fa, more auth options

* WIP getting auth stuff working

* Added Manage views. 2FA working now for MVC app.

* Switching to using a controller for no-UI logout scenario

* Adding Razor Pages impl of 2FA auth stuff. Works.

src/Web/ViewModels/Manage/ChangePasswordViewModel.cs

@@ -0,0 +1,25 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Microsoft.eShopWeb.ViewModels.Manage
+{
+    public class ChangePasswordViewModel
+    {
+        [Required]
+        [DataType(DataType.Password)]
+        [Display(Name = "Current password")]
+        public string OldPassword { get; set; }
+
+        [Required]
+        [StringLength(100, ErrorMessage = "The {0} must be at least {2} and at max {1} characters long.", MinimumLength = 6)]
+        [DataType(DataType.Password)]
+        [Display(Name = "New password")]
+        public string NewPassword { get; set; }
+
+        [DataType(DataType.Password)]
+        [Display(Name = "Confirm new password")]
+        [Compare("NewPassword", ErrorMessage = "The new password and confirmation password do not match.")]
+        public string ConfirmPassword { get; set; }
+
+        public string StatusMessage { get; set; }
+    }
+}