Add windows arm64 support.

Summary

Appreciation

First, I want to express my gratitude to the openconnect team for their excellent work.

Which problem does this feature request address?

I often feel frustrated when trying to use openconnect-gui on Windows ARM64 devices, as it only runs via emulation. This results in reduced performance and increased power consumption because the x64 version needs to be translated to run on ARM architecture. With the growing popularity of ARM64 devices like the Microsoft Surface Pro X, it's essential to have native support for better efficiency.

Describe the solution you'd like

I would like to see openconnect-gui provide native support for Windows ARM64. This would involve compiling the application specifically for the ARM64 architecture and ensuring compatibility of all dependencies. Native support would enhance performance and reduce power consumption, providing a smoother and more efficient user experience.

Alternatives you've considered

Currently, the only alternative is to use the x64 version of openconnect-gui through Windows' emulation. However, this approach negatively impacts performance and battery life. Other VPN clients that support ARM64 are available, but they may not offer the same features or user experience as openconnect-gui.

Additional context

As more devices transition to ARM64, native support will improve user experience and future-proof openconnect-gui. Assessing the feasibility of this transition and engaging with the community for testing and feedback could be beneficial. Supporting ARM64 could also expand the platform's user base and enhance its overall reach and usability.