Enable Qt WebEngine on Wayland

The native resource getters that are supported by eglfs will have to be
supported by the wayland platform plugin too. (on wayland-egl at least)

Change-Id: Ibbab649c04785dbde177342c45b9bc6f1edd954d
Reviewed-by: Andy Nichols <andy.nichols@theqtcompany.com>
Reviewed-by: Andras Becsi <andras.becsi@theqtcompany.com>