Enable sample applications as setup.py's entry points

[nbareil]

Hello Willi 👋

This PR enables setup.py to install some of the sample applications into the $PATH, that way, they are directly available after a pip install without having to find the path to the samples/ folders 🚀

I would have prefer to prefix their names with something unique but I had the writer's block :)

If you want me to add the other applications as well, no problem!