Domain fronting option

Summary

Which problem does this feature request addresses?

AFAIK, it's not possible to do domain fronting via the GUI client.

Describe the solution you'd like

Since OpenConnect v9.10, it's possible to pass --sni=example.com option to achieve domain fronting in order to bypass certain ISPs' network filtering attempts.

Alternatives you've considered

The current alternative is to simply use the CLI version.

Additional context

It would be great to have the option to provide --sni value in the GUI for more accessibility