[client]: improve batch request API

[niklasad1]

Close #909

After some discussions with Kian about the API in #909 it simply quite annoying for users to deal with i.e, to iterate over all responses to check whether it was successful but useful in some contexts such as if you want to exactly which requests failed.

After some suggestions by James, I reworked the API with an iterator-like API.

The responses still doesn't expose the request ID mainly because jsonrpsee controls the request IDs and changing that quite a big change and doesn't work well with the current BatchRequestBuilder.

Thus, the only way to map the requests to reponses is to copy the batch request and then iterate over the BatchResponse::into_iter together to figure it which calls that failed such as:

	let mut batch_request = BatchRequestBuilder::new();
	batch_request.insert("say_hello", rpc_params![]).unwrap();
	batch_request.insert("say_goodbye", rpc_params![0_u64, 1, 2]).unwrap();
	batch_request.insert("get_swag", rpc_params![]).unwrap();

        let response = client.batch_request(batch_request.clone()).await.unwrap();

        for (request, response) in batch_request.zip(response.iter()) {
            match response {
               Ok(r) => {
                   println!("request: {:?} succeed with response: {}", request, r); 
               }
               Err(err) => {
                   println!("request: {:?} failed with response: {}", request, err); 
               }
            }
        }

Ideally, the BatchRequestBuilder would inject the request IDs and allow users to add their own IDs but because we use the ID range as digest for each batch request it would make things harder.

Thus, I think this is good enough API for now.

[jsdw]

Looks great to me, ncie one!

[lexnv]

👍 LGTM!