introduce jsonrpsee client abstraction + kill HTTP support. (#341)

* PoC async rpc client

* add client example should be removed from this repo

* fmt

* cargo fmt

* subxt client tests

* cargo fmt

* fix some nits

* try nightly for all CI jobs

* need wasm also for CI

* wasm for nightly run too

* client: add missing features

* update jsonrpsee

* hacky update jsonrpsee

* use jsonrpsee crates.io release

* ci: pin nightly 2021-12-15

* pin nightly to 2021-12-15

* fix build

* fmt

* compile please

* rewrite me

* fixes

* fixes

* pre-generate metadata

* fix nit

* get rid of needless deps

* remove embedded client

* Update Cargo.toml

* Update subxt/Cargo.toml

* Update subxt/Cargo.toml

* Update subxt/src/client.rs

* Update subxt/src/rpc.rs

* Update test-runtime/build.rs

* cargo fmt

Co-authored-by: James Wilson <james@jsdw.me>

subxt/src/client.rs

@@ -86,7 +86,7 @@ impl ClientBuilder {
             client
         } else {
             let url = self.url.as_deref().unwrap_or("ws://127.0.0.1:9944");
-            RpcClient::try_from_url(url).await?
+            crate::rpc::ws_client(url).await?
         };
         let rpc = Rpc::new(client);
         let (metadata, genesis_hash, runtime_version, properties) = future::join4(