LaneletNetwork.translate_rotate() does not translate and rotate traffic signs

The lanelet network object handles all traffic signs yet does not rotate and translate them (it only translates the lanelets)

cf. the method in https://gitlab.lrz.de/tum-cps/commonroad_io/-/blob/master/commonroad/scenario/lanelet.py#L1129

Potential fix (including traffic lights and stop lines) can be found in https://gitlab.lrz.de/ge56vus/commonroad_io/-/commits/feature_translate_rotate_traffic_elems (I don't want to place this as a MR since it contains copy-pasta and no tests yet)