feat: implement ToMessage trait

[hashemix]

📌 Summary

Introduced new ToMessage Trait that simplifies the construction of MCP messages, reducing the amount of code required.

Example:

Before Introducing the ToMessage trait

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::Request(ServerJsonrpcRequest::new(
        request_id,
        RequestFromServer::ServerRequest(ServerRequest::PingRequest(ping_request)),
    ));

    // 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
}

After Introducing the ToMessage trait

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 = ping_request
        .to_message(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
}