Synced WazirX's official Python connector with the latest Postman collection

Unlike Go and Java, WazirX does publish an official Python connector. It had fallen behind the Postman collection: missing klines, my_trades, coins, withdraw/withdraw_history, deposit_address, and the sub-account transfer endpoints in both endpoints.py and api_mapper.json. I added them, and fixed a system_status mapping that incorrectly pointed at the time endpoint. Open as #19 .