This isn't necessary. Because we just log the error, we never match off of it,
we don't need any structure beyond String (or now Debug, which still gives us
a way to print the error). This is for the ergonomics of not having to
constantly write `.map_err(|e| format!("{e:?}"))`.
It's not only helpful (to easily check where Serai's view of the external
network is) but it's necessary in case of a non-trivial chain fork to determine
which blockchain Serai considers canonical.
This is incomplete at this time. The logic is fine, but needs to be moved to a
distinct location to handle singular blocks which produce multiple Batches.
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
`acknowledge_batch` can only be run if we know what the Batch should be. If we
don't know what the Batch should be, we have to block until we do.
Specifically, we need the block number associated with the Batch.
Instead of blocking over the Scanner API, the Scanner API now solely queues
actions. A new task intakes those actions once we can. This ensures we can
intake the entire Substrate chain, even if our daemon for the external network
is stalled at its genesis block.
All of this for the block number alone seems ridiculous. To go from the block
hash in the Batch to the block number without this task, we'd at least need the
index task to be up to date (still requiring blocking or an API returning
ephemeral errors).
