[jsonrpsee types]: provide macro for constructing JsonRpcParams

[niklasad1]

The JsonRpcParams are a little boiler-platy to provide as we require the arguments to be serde_json::Value,

Example:

// MyType doesn't implement `Into<serde_json::Value>`
let x: = MyType { };
let inner: &[JsonValue] = &[0_u32.into(), "hoo".to_string().into(), serde_json::to_value(x).unwrap()];
let params =  JsonRpcParams::ArrayRef(inner);

So it would be nice is to provide a macro such as params_positional! and params_object to avoid that.
Perhaps just provide a wrapper on-top of serde_json::json!?

Note: Copy @kianenigma's stuff.

[dvdplm]

Maybe it's possible to unify the client JsonRpcParams with the servers'?

[niklasad1]

Maybe it's possible to unify the client JsonRpcParams with the servers'?

The problem is that the server-side RpcParams is a wrapper over Cow<&str> and is used to deserialize the types within a request and JsonRpcParams is only used to serialize the types.

In order to unify them we would have to explicitly require to that user provide a &str/String for the params such as "[1, 2, "foo"]" which is very annoying in my experience. It could be possible to have that but we would still need some convenience method(s) to convert a Vec<T: serde::Serialize> to &str/String if that's possible to with a macro that would be awesome