Users API: Add roles (#1914)

* API: Fix create user response model

* API: Add roles to user data

BTCPayServer.Client/Models/ApplicationUserData.cs

@@ -21,5 +21,10 @@ namespace BTCPayServer.Client.Models
         /// whether the user needed to verify their email on account creation
         /// </summary>
         public bool RequiresEmailConfirmation { get; set; }
+
+        /// <summary>
+        /// the roles of the user
+        /// </summary>
+        public string[] Roles { get; set; }
     }
 }