Allow for more idiomatic Rust code

[thomaseizinger]

Currently, the functions on the trait need to be named exactly the way the RPC function is called. That means we cannot use idiomatic Rust naming conventions like snake_case.

We should support this in a similar fashion as serde with its rename_all attribute.

Potentially, we also want to allow prefixes like they are present in Web3's JSON-RPC API: eth_, web3_, net_` etc without having to repeat them on every function.

[thomaseizinger]

Another usecase for renaming is to handle requests like this one: https://www.getmonero.org/resources/developer-guides/daemon-rpc.html#get_block

With renaming we could define two different trait functions with different interfaces that end up being the same RPC call.