P3-Find a better way for including rank_llm in sys path.

[sahel-sh]

Currently we add the following snippet to every script that we want to run both from a cloned repo and using package installation. Ideally we should find a cleaner/simpler way

import sys
import os

SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
parent = os.path.dirname(SCRIPT_DIR)
parent = os.path.dirname(parent)
sys.path.append(parent)