Add delivery websocket endpoints

[nurdtechie98]

I have added delivery WebSocket endpoints, which isn't there at this point in time. All the endpoints covered in futures.
Most of it is a copy-paste of the corresponding futures part, with appropriate changes.
solves #453

[jaggedsoft]

Thank you very much for your contribution

[waterdrop01]

Hello @nurdtechie98 @jaggedsoft , any hint on how to subscribe to user data for delivery?

I have this code:

const onMarginCall = (res) => {
    debug('onMarginCall %o', res);
  };

  const onAccountUpdate = (res) => {
    debug('onAccountUpdate %o', res);
  };
  const onOrderUpdate = (res) => {
    debug('onOrderUpdate', res);
  };
  const onSubscribed = (res) => {
    debug('onSubscribed', res);
  };

  client.websockets.userFutureData(
    onMarginCall,
    onAccountUpdate,
    onOrderUpdate,
    onSubscribed,
  );

But when I move BTC from spot wallet to Futures "COIN-m" wallet, nothing is logged. Only transferring to USDT-m wallet will call "onAccountUpdate" function.

Is there an option to specify I want to subscribe to "COIN-m" or "delivery" futures websocket endpoint?

Thanks in advance for your help!