add csv& json

[XuhuiZhou]

Closes #

📑 Description

Adding helper function to serialize a list of episodes to csv or json format

✅ Checks

• [x] My pull request adheres to the code style of this project
• [x] My code requires changes to the documentation
• [x] I have updated the documentation as required
• [x] All the tests have passed
• [x] Branch name follows type/descript (e.g. feature/add-llm-agents)
• [x] Ready for code review

ℹ Additional Information