Make system lib usage optional (default = off)

ChromeOS doesn't have libwayland-server by default. Use Smithay's rust implementation instead. The primary impact this has is Renderer::bind_wl_display can no longer be used. This allows for interop between EGLDisplay and Wayland native buffers. In other words, disabling this and using typical EGL will result in poor performance. Luckily, this is not the case on Chrome.