WorldModel service calls become slow on busy ROS 2 network

[matthias-mayr]

When having the whole real WARA robotics setup in the same ROS_DOMAIN_ID, the world model interface service calls to the world model become very slow. It looked like 3-4 per second. This means that the skill manager needs several second per skill to launch. Starting a new skill takes at least one or two seconds.

I am not sure if this is an issue in our current usage of the ROS 2 service client. Maybe a MultiThreadedExecutor could help, but it would probably also have other implications.