[BFCL] Added reading_manager_api for multi-turn for BFCL

[shgguo]

I'm designing a collection called the ReadingManager API, which helps users manage reading goals and progress by providing functions for adding new books, tracking time spent reading, number of pages read, reading speed, and other metrics for reader progress.

[HuanzhiMao]

Thanks for the PR @shgguo.
Could you upload .py files instead? You can take a look at #691 for where that file should be placed and what we are looking for.

[shgguo]

I apologize. Converted the .ipynb file to .py and committed it to the path berkeley-function-call-leaderboard/bfcl/eval_checker/multi_turn_eval/func_source_code.