can't use ros1 and ros2 class_loader

[Karsten1987]

while developing rosbag2, we encountered that we have cyclic dependencies when trying to use ROS1 and ROS2 packages which both use their form of class loader. We worked around that by excluding "nodelets" from the ros1_bridge (as nodelets bring the dependency of class_loader).

see ros2/ros1_bridge#152

The original issue and description can be found here: ros2/rosbag2#69