Support V16 metadata and refactor metadata code (#1967)

* WIP integrate unstable v16 metadata into Subxt

* first pass moving retain to the CLI tool

* Remove otuer enum variant stripping and move now simpler strip_metadata to new crate. test it

* tidyup to use stripmetadata package etc

* Fix / comment out tests

* fmt

* clippy

* Fix wasm example

* wasm-example fix

* wasm-example fix

* Maske sure to move IDs around after types.retain()

* fmt

* Tweak comment

* Find dispatch error separately to avoid issues during mapping

* Expose associated type information in pallet metadata

* Hopefully fix flaky archive RPC

* remove unwanted temp file

* Address nits

* Add back commented-otu tests and address review comments

* use either, and simplify for_each

testing/ui-tests/Cargo.toml

@@ -16,4 +16,5 @@ frame-metadata = { workspace = true }
 codec = { package = "parity-scale-codec", workspace = true, features = ["derive", "bit-vec"] }
 subxt = { workspace = true, features = ["native", "jsonrpsee", "runtime-wasm-path"] }
 subxt-metadata = { workspace = true }
+subxt-utils-stripmetadata = { workspace = true }
 generate-custom-metadata = { path = "../generate-custom-metadata" }