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:?}"))`.
Moves the coordinator loop out of serai-bitcoin-processor, completing it.
Fixes a potential race condition in the message-queue regarding multiple
sockets sending messages at once.
