Further investigate how to sort the relays to create the circuits
The possible 2 hops permutations is very big.
We have the guard, middle and exit flags, so maybe we can create different subsets depending on the possible order.
We have other data that might be useful, for instance stable flag. Relays with stable flag might be less likely to fail, as well as relays with higher weight, but, should we rather try first relays more likely to fail?