enable extra gst-plugin-gtk4 features

We should add those features and enable them all when building on Linux. Runtime will automatically detect the one to use.

[features]
x11egl = ["gst-plugin-gtk4/x11egl"]
x11glx = ["gst-plugin-gtk4/x11glx"]
wayland = ["gst-plugin-gtk4/wayland"]

See https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/blob/main/video/gtk4/Cargo.toml?ref_type=heads