GitLab

- Remove DropMode and MakeMode imports from user code
- Set default drop_mode to DropMode.NONE in get_markdown and get_content_list methods
- Remove md_make_mode parameter from get_content_list method
- Add dump_middle_json method to PipeResult
- Update examples in API documentation and demo script

- Move __use_inside_model__ and __model_mode__ from operators/__init__.py to model/__init__.py
- These variables are more appropriately located in the model module since they relate to model configuration