Container issue: Facebook, Google, and external provider s

This is the Container issue for this doc. Reopen each issue you are working on so the owner is notified.

* authentication/sociallogins "Enabling authentication using Facebook, Google and other external providers" #1470 @wadepickett
* .AddDefaultUI(UIFramework.Bootstrap4) problem. "UIFramework" no longer exists. #15003

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#### Document Details

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* ID: d1612f19-f267-493a-c230-2ca18e4eb50b
* Version Independent ID: d312db0f-6cf1-87ca-09b0-604a66e18a07
* Content: [Facebook, Google, and external provider authentication in ASP.NET Core](https://docs.microsoft.com/en-us/aspnet/core/security/authentication/social/?view=aspnetcore-3.1&tabs=visual-studio)
* Content Source: [aspnetcore/security/authentication/social/index.md](https://github.com/aspnet/AspNetCore.Docs/blob/master/aspnetcore/security/authentication/social/index.md)
* Product: **aspnet-core**
* Technology: **aspnetcore-security**
* GitHub Login: @Rick-Anderson
* Microsoft Alias: **riande**