monero-wallet ships an Eventuality, yet it's across the entire transaction. It
can't prove a single output's state with a traditional payment proof. By adding
this new object, another library can obtain the ephemeral randomness used and
do any/every proof they want regarding a transaction's outputs.
Necessary for https://github.com/serai-dex/serai/issues/599.
* Rename the coins folder to networks
Ethereum isn't a coin. It's a network.
Resolves#357.
* More renames of coins -> networks in orchestration
* Correct paths in tests/
* cargo fmt
