Add TimmBackbone model (#22619)

* Add test_backbone for convnext

* Add TimmBackbone model

* Add check for backbone type

* Tidying up - config checks

* Update convnextv2

* Tidy up

* Fix indices & clearer comment

* Exceptions for config checks

* Correclty update config for tests

* Safer imports

* Safer safer imports

* Fix where decorators go

* Update import logic and backbone tests

* More import fixes

* Fixup

* Only import all_models if torch available

* Fix kwarg updates in from_pretrained & main rebase

* Tidy up

* Add tests for AutoBackbone

* Tidy up

* Fix import error

* Fix up

* Install nattan in doc_test_job

* Revert back to setting self._out_xxx directly

* Bug fix - out_indices mapping from out_features

* Fix tests

* Dont accept output_loading_info for Timm models

* Set out_xxx and don't remap

* Use smaller checkpoint for test

* Don't remap timm indices - check out_indices based on stage names

* Skip test as it's n/a

* Apply suggestions from code review

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

* Cleaner imports / spelling is hard

---------

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

utils/check_config_attributes.py

@@ -77,6 +77,7 @@ SPECIAL_CASES_TO_ALLOW = {
     "AutoformerConfig": ["num_static_real_features", "num_time_features"],
 }
 
+
 # TODO (ydshieh): Check the failing cases, try to fix them or move some cases to the above block once we are sure
 SPECIAL_CASES_TO_ALLOW.update(
     {
@@ -172,6 +173,8 @@ def check_attribute_being_used(config_class, attributes, default_value, source_s
         "mask_index",
         "image_size",
         "use_cache",
+        "out_features",
+        "out_indices",
     ]
     attributes_used_in_generation = ["encoder_no_repeat_ngram_size"]