Create a toy program to exercise the various Tor provider functionalities in Arti

Integrating Rust stuff in Firefox is kinda complex, because of how dependencies are managed etc etc (see #43096 and !1300 for some of my previous work with Lox).

Also, we don't know much about the current state of Arti, so it might be worth exploring.

As an idea, we could create a toy program outside Tor Browser to implement all our current TorProvider functionalities (or explore that).

This should allow us to set up a communication channel with the network team without having to deal with all the complications of Firefox.