Enable Kerberos authentication option in API template

[mkArtakMSFT]

This is listed in the Templating epic with questionmark, so not sure what exactly needs to happen here or how important it is to get it done in 3.0.

There is also tooling impact here. There is no such option in the New Project Dialog UI

This work depends on https://github.com/aspnet/AspNetCore/issues/8897

[mkArtakMSFT]

Talked to @blowdart regarding this. We aren't going to load templates with this. Rather there will be just docs covering enabling this.

[brockallen]

Don't forget to enable anti-forgery for the API calls.