### What problem does this PR solve?

Refactor API for document and session.

### Type of change


- [x] Refactoring

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

Fix: renrank_model and pdf_parser bugs | Update: session API
#2575
#2559
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] Refactoring

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

Includes SDK for creating, updating sessions, getting sessions, listing
sessions, and dialogues
#1102 
### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

SDK for session
#1102 

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Feiue <10215101452@stu.ecun.edu.cn>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>