Native namespace packages (PEP 420) (#2361)
* native namespace packages
* docstring
* test
* style
* test cli exprters and pipelines
* specify folder
* path :/
* fixes
* fix
* extend
* fix
* final fix
* only keep one way for registering commands
* remove print
* revert load_subpackages
* style
* trigger
* pip uninstall optimum optimum-onnx
* try using less of macos 15 (because of provisions)
* test provision issue with macos 14
* fix node version for docs
* use one macos 15
* use macos 14
* no need to test macos everywhere
* better command registration that avoids importing the subpackages and only import the commands
