Added demo trading (Not tested)

[demonarch]

Demo Trading Guidelines

For real trading on BingX, base url must be (and used to be in python-bingx-connector):

https://open-api.bingx.com

To facilitate demo trading on BingX, base URL must be set to the VST api:

https://open-api-vst.bingx.com

Overview

This commit introduces an enhancement to the API client for improved clarity. A new variable named 'mode' has been introduced, set to 'demo' by default. This addition aims to provide developers with better awareness when executing trades; Also enabling them to execute demo trades.

Usage Instructions

When interacting with your demo account or conducting demo trades, simply utilize the existing default value 'demo' for the 'mode' variable. Conversely, if you intend to execute real trades or interact with your real account, it's imperative to explicitly set the 'mode' variable to 'real'.

Examples

Default mode (demo):

from bingX.perpetual.v2 import Perpetual

# Demo mode by default
client = Perpetual(api_key, api_secret)
balance = client.balance(rec)
print(balance)
positions = client.positions('BTC-USDT')
print(positions)

Explicitly setting mode to 'demo':

from bingX.perpetual.v2 import Perpetual

# Explicitly setting to demo mode
client = Perpetual(api_key, api_secret, mode='demo')
balance = client.balance(rec)
print(balance)
client.trade_order(
    symbol='BTC-USDT',
    type='market',
    side='buy',
    quantity=0.001,
)

Explicitly setting mode to 'real' (For executing real trades or interacting with real accounts), please use with awareness in your responsibility:

from bingX.perpetual.v2 import Perpetual

# Explicitly setting to real mode
client = Perpetual(api_key, api_secret, mode='real')
balance = client.balance(rec)
print(balance)
client.trade_order(
    symbol='BTC-USDT',
    type='market',
    side='buy',
    quantity=0.001,
)