Create Users Manually (Email still required) (#1381)

* Implemented a manual button to allow users to setup an account, even after they invited.

Updated error toast to put "Error" in the title of the toast.

* Updated the exception middleware to always send full context instead of generic "Internal Server Error"

API/Entities/AppUser.cs

@@ -25,6 +25,10 @@ namespace API.Entities
         /// An API Key to interact with external services, like OPDS
         /// </summary>
         public string ApiKey { get; set; }
+        /// <summary>
+        /// The confirmation token for the user (invite). This will be set to null after the user confirms.
+        /// </summary>
+        public string ConfirmationToken { get; set; }
 
 
         /// <inheritdoc />