GitLab

* add first generation tutorial

* [from_pretrained] Allow loading models from subfolders

* remove gen file

* add doc strings

* allow download from subfolder

* add tests

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

* apply comments

* correct doc string
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>