Renaming CatalogServices to CatalogViewModelService

- I believe this causes some confusion when people see "Service" in the Web project. We have another service in there named BasketViewModelService instead of BasketService anyways. Adding "ViewModel" to the name is a better representation of what the "services" in the Web project represent.

src/Web/Interfaces/ICatalogViewModelService.cs

@@ -5,7 +5,7 @@ using System.Threading.Tasks;
 
 namespace Microsoft.eShopWeb.Web.Services
 {
-    public interface ICatalogService
+    public interface ICatalogViewModelService
     {
         Task<CatalogIndexViewModel> GetCatalogItems(int pageIndex, int itemsPage, int? brandId, int? typeId);
         Task<IEnumerable<SelectListItem>> GetBrands();