Rename the two cursor role types according to the convention used by the
other roles. This means that MetaWaylandSurfaceRoleCursor was renamed to
MetaWaylandCursorSurface, and MetaWaylandSurfaceRoleTabletCursor was
renamed to MetaWaylandTabletCursorSurface. The corresponding filenames
were renamed accordingly too.
https://gitlab.gnome.org/GNOME/mutter/issues/77
