Merge LiT5 into RankLLM

[17Melissa]

Reference URA-Project

Issue 35 RankLLM: Merge LiT5 Models into RankLLM castorini/ura-projects#35

The goal is to port LiT5-Distill and LiT5-Score over to RankLLM.

Completed

• Synced the LiT5 integration structure with the latest master, from command-line execution to the rankllm class
• Built RankFiDDistill(RankLLM) and RankFiDScore(RankLLM) in rank_fid.py
• Built LiT5DistillReranker and LiT5ScoreReranker in lit5_reranker.py

Next Steps

• Inherited functions in RankFiDDistill, like create_prompt and run_llm, still need adjustments and testing to ensure LiT5 performs correctly
• Implemented inherited functions in RankFiDScore
• Validate the process of using LiT5 models within RankLLM, ideally we have a central command so run LiT5 as python src/rank_llm/scripts/run_rank_llm.py with --args