Set 'raster-fade-duration': 0 for smooth layer animation

[wkramer]

For smooth animation we load the new layer with opacity 0. When completely loaded the opacity of the new layer set to 1 and the old layer is set to 0 and removed.
There should be no fade between the old and new layer with the option 'raster-fade-duration': 0.
This option triggers a but when zooming tiles: mapbox/mapbox-gl-js#12241