Remove broken gstreamer-vaapi
gstreamer-vaapi is currently totally busted for me due to https://gitlab.freedesktop.org/gstreamer/gstreamer-vaapi/issues/100
Although there has been some progress on fixing that bug, this is production software and we shouldn't wait around when we can make video playback work now by just removing this plugin.
@jjardon, can we remove it from the runtime for the time being?