Renames Update to SignedBatch.
Checks Batch equality via a hash of the InInstructions. That prevents needing
to keep the Batch in node state or TX introspect.
The Processor's coins folder referred to the networks it could process, as did
its Coin trait. This, and other similar cases throughout the codebase, have now
been corrected.
Also corrects dated documentation for a key pair is confirmed under the
validator-sets pallet.
Writes a custom unsigned extrinic creator due to subxt having an internal error
with the scale metadata. While the code in our scope increased, it's much more
ergonomic to our usage. We may end up rewriting most of subxt, eventually.
