[Quantization] Quanto quantizer (#29023)

* start integration

* fix

* add and debug tests

* update tests

* make pytorch serialization works

* compatible with device_map and offload

* fix tests

* make style

* add ref

* guard against safetensors

* add float8 and style

* fix is_serializable

* Fix shard_checkpoint compatibility with quanto

* more tests

* docs

* adjust memory

* better

* style

* pass tests

* Update src/transformers/modeling_utils.py

Co-authored-by: Younes Belkada <49240599+younesbelkada@users.noreply.github.com>

* add is_safe_serialization instead

* Update src/transformers/quantizers/quantizer_quanto.py

Co-authored-by: Younes Belkada <49240599+younesbelkada@users.noreply.github.com>

* add QbitsTensor tests

* fix tests

* simplify activation list

* Update docs/source/en/quantization.md

Co-authored-by: David Corvoysier <david.corvoysier@gmail.com>

* better comment

* Update tests/quantization/quanto_integration/test_quanto.py

Co-authored-by: David Corvoysier <david.corvoysier@gmail.com>

* Update tests/quantization/quanto_integration/test_quanto.py

Co-authored-by: David Corvoysier <david.corvoysier@gmail.com>

* find and fix edge case

* Update docs/source/en/quantization.md

Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>

* pass weights_only_kwarg instead

* fix shard_checkpoint loading

* simplify update_missing_keys

* Update tests/quantization/quanto_integration/test_quanto.py

Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>

* recursion to get all tensors

* block serialization

* skip serialization tests

* fix

* change by cuda:0 for now

* fix regression

* update device_map

* fix doc

* add noteboon

* update torch_dtype

* update doc

* typo

* typo

* remove comm

---------

Co-authored-by: Younes Belkada <49240599+younesbelkada@users.noreply.github.com>
Co-authored-by: David Corvoysier <david.corvoysier@gmail.com>
Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>
Co-authored-by: Younes Belkada <younesbelkada@gmail.com>

src/transformers/testing_utils.py

@@ -89,6 +89,7 @@ from .utils import (
     is_pytesseract_available,
     is_pytest_available,
     is_pytorch_quantization_available,
+    is_quanto_available,
     is_rjieba_available,
     is_sacremoses_available,
     is_safetensors_available,
@@ -1043,6 +1044,13 @@ def require_auto_awq(test_case):
     return unittest.skipUnless(is_auto_awq_available(), "test requires autoawq")(test_case)
 
 
+def require_quanto(test_case):
+    """
+    Decorator for quanto dependency
+    """
+    return unittest.skipUnless(is_quanto_available(), "test requires quanto")(test_case)
+
+
 def require_phonemizer(test_case):
     """
     Decorator marking a test that requires phonemizer