add wasm support (#700)

* get started

* make it work again

* make it compile again

* Use async-wasm-feature of jsonrpsee from the master branch

* Ensure we enable JS feature of getrandom for the wasm target

* Update subxt/src/lib.rs

* update jsonrpsee

* fix CI

* cargo fmt

* fix wasm test

* fix grumbles

* exclude wasm-tests from workspace

To avoid leaking `jsonrpsee-web` feature into the workspace

Co-authored-by: Igor Matuszewski <xanewok@gmail.com>

testing/wasm-tests/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "wasm-test"
+version = "0.1.0"
+edition = "2021"
+
+[dev-dependencies]
+wasm-bindgen-test = "0.3.24"
+tracing-wasm = "0.2.1"
+console_error_panic_hook = "0.1.7"
+serde_json = "1.0.57"
+subxt = { path = "../../subxt", default-features = false, features = ["jsonrpsee-web"] }