GitLab

* add warning on 8-bit models

- added tests
- added wrapper

* move to a private attribute

- remove wrapper
- changed `save_pretrained` method

* Apply suggestions from code review
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

* fix suggestions
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>