Add visualization scripts

[CihatAltiparmak]

Maybe you can add a small section here how to visualize the results (You can also open an issue and do that in a follow-up PR)

Originally posted by @sjahr in #5 (comment)

I actually implemented visualizer script in python. It would be great to prepare visualization relavant stuff in follow-up PR. But if you wonder it, i run benchmarks separately per each middleware (rmw_zenoh, rmw_cyclonedds and rmw_fastrtps). Then i move this files to where the script is located and run scripts. Box plot is created magically after running script. Script is [here](https://gist.github.com/CihatAltiparmak/899090aca71223fbb964569f83265a49).

Originally posted by @CihatAltiparmak in #5 (comment)