Add SNI for JWT policy

[anderius]

Is your feature request related to a problem? Please describe.

Network rules often rely on SNI to work, and we noticed that Nginx is not always sending the server name.

Describe the solution you'd like

One example is here: https://github.com/nginx/kubernetes-ingress/blob/main/internal/configs/version2/nginx-plus.virtualserver.tmpl#L230

It would be nice if all proxy_pass / external subrequests set SNI, like it is done here:

proxy_ssl_server_name on; # For SNI to the IdP

Describe alternatives you've considered

None. Workaround is to use IP-addresses in firewalls etc.

Additional context

None.