Llamafactory

- Web UI: source_prefix, max_length, dev set
- Bug fix: reward token 179
- Update template 171 177
- Bug fix: replace the Literal type with Enum for pydantic [1] 176
- Add Web demo 180

[1] https://github.com/pydantic/pydantic/issues/5821, https://github.com/tiangolo/sqlmodel/issues/67

- Fix gradient accumulation in PPO Trainer https://github.com/hiyouga/ChatGLM-Efficient-Tuning/issues/299
- All-in-one Web UI by hiyouga , KanadeSiina and codemayq