Fixing/Adding example for p2p_discovery

[Huy-Nguyen-web]

Hi, I've noticed that DefNet had a breaking change since the version 6.0.0, and that also create some issues to the p2p_discovery example.

When running the p2p_discovery example, after the client found a host, the logo instead of doing the animation, it's flying up through the screen.

My suggestion is to add self.p2p.stop in the current example, and create a new example without the stop function after the client found a server, so that people can decide whether or not they need to use the stop function in their project (or in which scenario that they might need).

[britzl]

Thanks. I opted for simply stopping discovery at that point. I think that is enough.