Use scale-encode and scale-decode to encode and decode based on metadata (#842)

* WIP EncodeAsType and DecodeAsType

* remove silly cli experiment code

* Get things finally compiling with EncodeAsType and DecodeAsType

* update codegen test and WrapperKeepOpaque proper impl (in case it shows up in codegen)

* fix tests

* accomodate scale-value changes

* starting to migrate to EncodeAsType/DecodeAsType

* static event decoding and tx encoding to use DecodeAsFields/EncodeAsFields

* some tidy up and add decode(skip) attrs where needed

* fix root event decoding

* #[codec(skip)] will do, and combine map_key stuff into storage_address since it's all specific to that

* fmt and clippy

* update Cargo.lock

* remove patched scale-encode

* bump scale-encode to 0.1 and remove unused dep in testing crate

* update deps and use released scale-decode

* update scale-value to latest to remove git branch

* Apply suggestions from code review

Co-authored-by: Alexandru Vasile <60601340+lexnv@users.noreply.github.com>

* remove sorting in derives/attr generation; spit them out in order given

* re-add derive sorting; it's a hashmap

* StaticTxPayload and DynamicTxPayload rolled into single Payload struct

* StaticStorageAddress and DynamicStorageAddress into single Address struct

* Fix storage address byte retrieval

* StaticConstantAddress and DynamicConstantAddress => Address

* Simplify storage codegen to fix test

* Add comments

* Alias to RuntimeEvent rather than making another, and prep for substituting call type

* remove unnecessary clone

* Fix docs and failing UI test

* root_bytes -> to_root_bytes

* document error case in StorageClient::address_bytes()

---------

Co-authored-by: Alexandru Vasile <60601340+lexnv@users.noreply.github.com>

testing/integration-tests/src/codegen/mod.rs

@@ -5,10 +5,11 @@
 /// Checks that code generated by `subxt-cli codegen` compiles. Allows inspection of compiler errors
 /// directly, more accurately than via the macro and `cargo expand`.
 ///
-/// Generate by:
+/// Generate by running this at the root of the repository:
 ///
-/// - run `polkadot --dev --tmp` node locally
-/// - `cargo run -p subxt-cli -- codegen | rustfmt > testing/integration-tests/src/codegen/polkadot.rs`
+/// ```
+/// cargo run --bin subxt -- codegen --file artifacts/polkadot_metadata.scale | rustfmt > testing/integration-tests/src/codegen/polkadot.rs
+/// ```
 #[rustfmt::skip]
 #[allow(clippy::all)]
 mod polkadot;