Membership provider for .net Core 2.0 Web API

I have been doing MySql based membership provider from years in Asp.net Webforms, now switched to Dot Net Core 2.0 Web API. Was trying to get the same approach done but System.Web.Security is missing, maybe for a good reason which I not aware of.

I have gone through Identity Server 4.0 but it is not meant for Registrations purpose. So looking for a similar solution to Old MySql way, have tried JWT Authentication too but nothing is of that sort.

May I know what happened to Membership provider and what approach I use to get it done.