Issue 2: Code Duplication

[PrinceSajjadHussain]

Title: Code Duplication Between Files: Consolidate fetch_binance_ohlcv Function

Body:
The fetch_binance_ohlcv function is duplicated in both backtesting_tool.py and strategy-update-backtest.py. This violates the DRY (Don't Repeat Yourself) principle and makes maintenance more difficult.

To address this, extract the fetch_binance_ohlcv function into a separate module (e.g., data_fetcher.py) and import it into both scripts. This will ensure that any changes or bug fixes to the data fetching logic are applied consistently across all scripts.

# data_fetcher.py
import requests
import pandas as pd

def fetch_binance_ohlcv(symbol, interval='1d', limit=365):
    # ... (Implementation of fetch_binance_ohlcv)
    pass

Then, in both backtesting_tool.py and strategy-update-backtest.py:

from data_fetcher import fetch_binance_ohlcv

This refactoring reduces code duplication and improves maintainability.