Centralize logging (#6434)

* Logging

* Style

* hf_logging > utils.logging

* Address @thomwolf's comments

* Update test

* Update src/transformers/benchmark/benchmark_utils.py

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

* Revert bad change

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

tests/test_logging.py

@@ -0,0 +1,20 @@
+import unittest
+
+from transformers import logging
+
+
+class HfArgumentParserTest(unittest.TestCase):
+    def test_set_level(self):
+        logger = logging.get_logger()
+
+        logging.set_verbosity_error()
+        self.assertEqual(logger.getEffectiveLevel(), logging.get_verbosity())
+
+        logging.set_verbosity_warning()
+        self.assertEqual(logger.getEffectiveLevel(), logging.get_verbosity())
+
+        logging.set_verbosity_info()
+        self.assertEqual(logger.getEffectiveLevel(), logging.get_verbosity())
+
+        logging.set_verbosity_debug()
+        self.assertEqual(logger.getEffectiveLevel(), logging.get_verbosity())