wayland: early aspect calculation in vo_config

Calculate the aspect ratio in vo_config, when we get the window size and in the
inside the resize function we calculate the aspect ratio of the output in order
to determine if we have to change the height or the width of the video.

If the ratio of the output is bigger than the ratio of the video then we have
to set the width accordingly and if the ratio is smaller we change the size.
But only if no resize edges are passed, because this indicates that we want to
change the windows state instead of just a simple resize and the video should
not grow bigger than the requested size.