It makes sense for networks which support arbitrary data to do as part of their
address. This reduces the ability to perform DoSs, achieves better performance,
and better uses the type system (as now networks we don't support data on don't
have a data field).
Updates the Ethereum address definition in serai-client accordingly
I don't love this, but it's the only way to select decoys without using a local
database. While the prior commit added such a databse, the performance of it
presumably wasn't viable, and while TODOs marked the needed improvements, it
was still messy with an immense scope re: any auditing.
The relevant scheduler functions now take `&self` (intentional, as all
mutations should be via the `&mut impl DbTxn` passed). The calls to `&self` are
expected to be completely deterministic (as usual).
The main benefit is whatever scheduler is in use, we now have a single API to
receive TXs to sign (which is of value to the TX signer crate we'll inevitably
build).
