feat: introduce FromMessage trait

[hashemix]

📌 Summary

Introduced a new trait named FromMessage, this is useful for transforming mcp messages into another Type that could be serialized into a JsonrpcMessage.

For example, a ServerMessage can be constructed from a rust_mcp_schema::PingRequest by attaching a RequestId.
Eventually, the ServerMessage can be serialized into a valid JsonrpcMessage for transmission over the transport.

Example:

async fn send_ping_request(ping_request: rust_mcp_schema::PingRequest){

    let request_id = get_next_id();

    // construct a ServerMessage from the ping_request , with request_id
    let message = ServerMessage::from_message(
        MessageFromServer::RequestFromServer(ping_request.into()),
        request_id,
    ).unwrap();

    // serialize message into a valid rpcJsonrpcMessage string
    let rpc_message_json_str = message.to_string();

    // send the ping request to the client
    tranport.send(rpc_message_json_str).await

}