Support rotation for raster content in eglfs

QWS' rotate parameter is completely unsupported. This means that widget apps have no sane way of rotating their content, which can be very problematic on embedded devices where the display needs to be usable in orientations different than its natural orientation.

With eglfs it would be relatively straightforward to do the rotation in an accelerated manner during the composition of the widget quads.

Maybe consider it for linuxfb too. Not sure if it is worth it there though.