Plot: Ability to clear data

[ljburtz]

an important feature for my workflow -> after setting up foxglove and the data connection to ROS, I need to 'clear the plots / data", then start the test (e.g send commands to the robot)

this is needed to get clean plots (without the setting up garbage at the start).

In plotjuggler, the keyboard shortcut Ctrl-Shift-C makes this a breeze is there something similar in foxglove?

I tested the Ctrl-R in foxglove but this also resets the datasource connection (autoreconects but takes a while) and might also reset other unwanted settings / unsaved layouts?

It would make for a better workflow to have a keyboard shortcut for clearing just the plots / data buffers