Automatically show demo statistics when launching the demo

[carlossvg]

Description

When launching the demo with launch it would be great to show the demo statistics live at the same time the pendulum simulation is shown in rviz. This could be automated using ros2 topic echo or a logger node with ros2 launch, for example.

Ideally, we would show the statistics in live plots using Plotjugler currently it is not possible to filter a topic by a string field, which is required to plot topic statistics.

We could consider also using tmux to create different display windows. See this example.