Mediatr example (#325)

* Updates based on documentation

* Getting the build passing

* Getting app functioning

* A few cleanups to confirm it's working as expected

* Fixing functional tests

* Updating dockerfile for 3.0

* Functional Tests now run sequentially

* Updating to latest version of moq

* Adding migration for post 3.0 upgrades

* Removing commented out lines

* Moving address and catalogitemordered configuration in to classes that own them

* Installing MediatR nuget packages

* Configure MediatR in Startup

* Creating GetMyOrders MediatR query and handler

* Adding GetOrderDetails MediatR handler

* Refactoring out default values

* Added tests for GetOrderDetails mediator handler

* Defaulting values on Models for now

* Removing some spaces

* Splitting files

* Splitting out the GetOrderDetails files

* Adding test for GetMyOrders

* restructuing folders

* Using constant

src/Web/Features/MyOrders/GetMyOrdersHandler.cs

@@ -0,0 +1,43 @@
+using MediatR;
+using Microsoft.eShopWeb.ApplicationCore.Interfaces;
+using Microsoft.eShopWeb.ApplicationCore.Specifications;
+using Microsoft.eShopWeb.Web.ViewModels;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.eShopWeb.Web.Features.MyOrders
+{
+    public class GetMyOrdersHandler : IRequestHandler<GetMyOrders, IEnumerable<OrderViewModel>>
+    {
+        private readonly IOrderRepository _orderRepository;
+
+        public GetMyOrdersHandler(IOrderRepository orderRepository)
+        {
+            _orderRepository = orderRepository;
+        }
+
+        public async Task<IEnumerable<OrderViewModel>> Handle(GetMyOrders request, CancellationToken cancellationToken)
+        {
+            var specification = new CustomerOrdersWithItemsSpecification(request.UserName);
+            var orders = await _orderRepository.ListAsync(specification);
+
+            return orders.Select(o => new OrderViewModel
+            {
+                OrderDate = o.OrderDate,
+                OrderItems = o.OrderItems?.Select(oi => new OrderItemViewModel()
+                {
+                    PictureUrl = oi.ItemOrdered.PictureUri,
+                    ProductId = oi.ItemOrdered.CatalogItemId,
+                    ProductName = oi.ItemOrdered.ProductName,
+                    UnitPrice = oi.UnitPrice,
+                    Units = oi.Units
+                }).ToList(),
+                OrderNumber = o.Id,
+                ShippingAddress = o.ShipToAddress,
+                Total = o.Total()
+            });
+        }
+    }
+}