Rework Linux/BSD mobile simulator to use GLFW

[Jacalz]

Checklist

• I have searched the issue tracker for open issues that relate to the same feature, before opening a new one.
• This issue only relates to a single feature. I will open new issues for any other features.

Is your feature request related to a problem?

The mobile simulator on Linux and BSD currently has a custom x11 implementation when running on Linux and BSD, see https://github.com/fyne-io/fyne/blob/master/internal/driver/mobile/app/x11.go and https://github.com/fyne-io/fyne/blob/master/internal/driver/mobile/app/x11.c. This is complicated to maintain (#591 for example) and does not support Wayland. It seems to me like it would be better to let glfw abstract all of that for us.

Is it possible to construct a solution with the existing API?

Yes

Describe the solution you'd like to see.

Use GLFW for mobile simulator on Linux and BSD plus add Wayland support. It should be a lot easier to implement #591 after this.