Support constructing and submitting V5 transactions (#1931)

* TransactionExtensions basic support for V5 VerifySignature and renames

* WIP: subxt-core v5 transaction support

* Subxt to support V5 extrinsics

* WIP tests failing with wsm trap error

* Actually encode mortality to fix tx encode issue

* fmt

* rename to sign_with_account_and_signature

* Add explicit methods for v4 and v5 ext construction

* clippy

* fix wasm example and no mut self where not needed

* fix doc example

* another doc fix

* Add tests for tx encoding and fix v5 encode issue

* add copyright and todo

* refactor APIs to have clear v4/v5 split in core and slightly nicer split in subxt proper

* rename Partial/SubmittableExtrinsic to *Transaction

* Remove SignerT::address since it's not needed

* doc fixes

* fmt

* doc fixes

* Fix comment number

* Clarify panic behaviour of inject_signature

* fmt

subxt/src/lib.rs

@@ -57,10 +57,10 @@ pub mod utils;
 /// Polkadot node.
 pub mod config {
     pub use subxt_core::config::{
-        polkadot, signed_extensions, substrate, BlockHash, Config, DefaultExtrinsicParams,
+        polkadot, substrate, transaction_extensions, BlockHash, Config, DefaultExtrinsicParams,
         DefaultExtrinsicParamsBuilder, ExtrinsicParams, ExtrinsicParamsEncoder, Hasher, Header,
-        PolkadotConfig, PolkadotExtrinsicParams, RefineParams, RefineParamsData, SignedExtension,
-        SubstrateConfig, SubstrateExtrinsicParams,
+        PolkadotConfig, PolkadotExtrinsicParams, SubstrateConfig, SubstrateExtrinsicParams,
+        TransactionExtension,
     };
     pub use subxt_core::error::ExtrinsicParamsError;
 }