make `uname -s -v -n -r -m` say something for fun

[benbot]

I notice a lot of bots that get trapped in pisshoff start off by running uname -s -v -n -r -m, but then disconnect after the command fails

It'd be pretty interesting to be able to configure specific responses for some commands like this.

I'm pretty new to rust, but I may take a shot at adding this.