add MobileViT model (#17354)

* add MobileViT

* fixup

* Update README.md

Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

* remove empty line

Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

* use clearer variable names

* rename to MobileViTTransformerLayer

* no longer inherit from nn.Sequential

* fixup

* fixup

* not sure why this got added twice

* rename organization for checkpoints

* fix it up

* Update src/transformers/models/mobilevit/__init__.py

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

* Update src/transformers/models/mobilevit/configuration_mobilevit.py

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

* Update src/transformers/models/mobilevit/configuration_mobilevit.py

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

* Update src/transformers/models/mobilevit/configuration_mobilevit.py

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

* Update tests/models/mobilevit/test_modeling_mobilevit.py

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

* Update src/transformers/models/mobilevit/modeling_mobilevit.py

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

* Update src/transformers/models/mobilevit/modeling_mobilevit.py

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

* Update src/transformers/models/mobilevit/modeling_mobilevit.py

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

* Update src/transformers/models/mobilevit/modeling_mobilevit.py

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

* code style improvements

* fixup

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

Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

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

Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

* Update src/transformers/models/mobilevit/configuration_mobilevit.py

Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

* Update src/transformers/models/mobilevit/configuration_mobilevit.py

Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

* download labels from hub

* rename layers

* rename more layers

* don't compute loss in separate function

* remove some nn.Sequential

* replace nn.Sequential with new MobileViTTransformer class

* replace nn.Sequential with MobileViTMobileNetLayer

* fix pruning since model structure changed

* fixup

* fix doc comment

* remove custom resize from feature extractor

* fix ONNX import

* add to doc tests

* use center_crop from image_utils

* move RGB->BGR flipping into image_utils

* fix broken tests

* wrong type hint

* small tweaks

Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

docs/source/en/serialization.mdx

@@ -75,6 +75,7 @@ Ready-made configurations include the following architectures:
 - Marian
 - mBART
 - MobileBERT
+- MobileViT
 - OpenAI GPT-2
 - Perceiver
 - PLBart