Reorganize file utils (#16264)

* Split file_utils in several submodules

* Fixes

* Add back more objects

* More fixes

* Who exactly decided to import that from there?

* Second suggestion to code with code review

* Revert wront move

* Fix imports

* Adapt all imports

* Adapt all imports everywhere

* Revert this import, will fix in a separate commit

tests/test_modeling_common.py

@@ -40,7 +40,6 @@ from transformers import (
     is_torch_available,
     logging,
 )
-from transformers.file_utils import WEIGHTS_NAME, is_flax_available, is_torch_fx_available
 from transformers.models.auto import get_values
 from transformers.testing_utils import (
     PASS,
@@ -55,6 +54,7 @@ from transformers.testing_utils import (
     slow,
     torch_device,
 )
+from transformers.utils import WEIGHTS_NAME, is_flax_available, is_torch_fx_available
 
 
 sys.path.append(str(Path(__file__).parent.parent / "utils"))