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

examples/tensorflow/question-answering/run_qa.py

@@ -41,8 +41,7 @@ from transformers import (
     TFTrainingArguments,
     set_seed,
 )
-from transformers.file_utils import CONFIG_NAME, TF2_WEIGHTS_NAME
-from transformers.utils import check_min_version
+from transformers.utils import CONFIG_NAME, TF2_WEIGHTS_NAME, check_min_version
 from utils_qa import postprocess_qa_predictions