### What problem does this PR solve?
1. Fix typos
2. Rename function
3. Use English to write comment
### Type of change
- [x] Refactoring
Signed-off-by: jinhai <haijin.chn@gmail.com>
### What problem does this PR solve?
Add file convert to document API just like file2document_app.py
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Add file management HTTP_API for operating files
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
