Swamy/remove unused usings and reorganize usings (#489)

* Removed and Reordered the using statements

* Removed and Reordered the usings inside Web Project

* Removed and Reordered the usings inside PublicApi project

* Removed Unused usings and reorganized usings inside Infrastructure project

tests/FunctionalTests/PublicApi/ApiTokenHelper.cs

@@ -1,5 +1,4 @@
 using Microsoft.eShopWeb.ApplicationCore.Constants;
-using Microsoft.eShopWeb.Infrastructure.Identity;
 using Microsoft.IdentityModel.Tokens;
 using System;
 using System.Collections.Generic;