Simplify creating and signing extrinsics (#490)

* WIP extrinsic api updates

* First pass done; now to get things compiling again

* document and tweak new structs/traits

* cargo check --all-targets now compiles without issue

* Polkadot and Substrate take different extra params; support both

* Fix transaction format (missing byte from AccountId -> Address) and fmt

* Tweak Signer trait

* Tweak comments and such in extrinsic params

* check all examples against newer polkadot, add new one with params, import path tweaks

* clippy fix, and save an allocation when signing

* Remove unnecessary Default clauses

* Tidy up and fix comments. Panic if payload size >4GB

* fix typo

codegen/src/api/mod.rs

@@ -288,7 +288,7 @@ impl RuntimeGenerator {
                 impl<T, X> ::core::convert::From<::subxt::Client<T>> for RuntimeApi<T, X>
                 where
                     T: ::subxt::Config,
-                    X: ::subxt::SignedExtra<T>
+                    X: ::subxt::extrinsic::ExtrinsicParams<T>
                 {
                     fn from(client: ::subxt::Client<T>) -> Self {
                         Self { client, marker: ::core::marker::PhantomData }
@@ -298,7 +298,7 @@ impl RuntimeGenerator {
                 impl<'a, T, X> RuntimeApi<T, X>
                 where
                     T: ::subxt::Config,
-                    X: ::subxt::SignedExtra<T>,
+                    X: ::subxt::extrinsic::ExtrinsicParams<T>,
                 {
                     pub fn constants(&'a self) -> ConstantsApi {
                         ConstantsApi
@@ -368,7 +368,7 @@ impl RuntimeGenerator {
                 impl<'a, T, X> TransactionApi<'a, T, X>
                 where
                     T: ::subxt::Config,
-                    X: ::subxt::SignedExtra<T>,
+                    X: ::subxt::extrinsic::ExtrinsicParams<T>,
                 {
                     #(
                         pub fn #pallets_with_calls(&self) -> #pallets_with_calls::calls::TransactionApi<'a, T, X> {