AutoImageProcessor (#20111)

* AutoImageProcessor skeleton

* Update references

* Add mapping in init

* Add model image processors to __init__ for importing

* Add AutoImageProcessor tests

* Fix up

* Image Processor documentation

* Remove pdb

* Update docs/source/en/model_doc/mobilevit.mdx

* Update docs

* Don't add whitespace on json files

* Remove fixtures

* Move checking model config down

* Fix up

* Add check for image processor

* Remove FeatureExtractorMixin in docstrings

* Rename model_tmpfile to config_tmpfile

* Don't make None if not in image processor map

docs/source/en/model_doc/convnext.mdx

@@ -33,7 +33,7 @@ Tips:
 - See the code examples below each model regarding usage.
 
 <img src="https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/convnext_architecture.jpg"
-alt="drawing" width="600"/> 
+alt="drawing" width="600"/>
 
 <small> ConvNeXT architecture. Taken from the <a href="https://arxiv.org/abs/2201.03545">original paper</a>.</small>
 
@@ -50,6 +50,11 @@ This model was contributed by [nielsr](https://huggingface.co/nielsr). TensorFlo
 [[autodoc]] ConvNextFeatureExtractor
 
 
+## ConvNextImageProcessor
+
+[[autodoc]] ConvNextImageProcessor
+    - preprocess
+
 ## ConvNextModel
 
 [[autodoc]] ConvNextModel
@@ -71,4 +76,4 @@ This model was contributed by [nielsr](https://huggingface.co/nielsr). TensorFlo
 ## TFConvNextForImageClassification
 
 [[autodoc]] TFConvNextForImageClassification
-    - call
+    - call