[WIP] Resnet (#15770)

* first commit

* ResNet model correctly implemented.

basic modeling + weights conversion is done

removed unused doc

mdx file

doc and conversion script

added feature_extractor to auto

test

minor changes + style + quality

doc

test

Delete process.yml

A left over from my attempt of running circleci locally

* minor changes

* Apply suggestions from code review
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

* new test format

* minor changes from conversations

* minor changes from conversations

* make style + quality

* readded the tests

* test + README

* minor changes from conversations

* error in README

* make fix-copies

* removed regression for classification head

* make quality

* fixed loss control flow

* fixed loss control flow

* resolved conversations

* Apply suggestions from code review
Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

* READMEs

* index.mdx

* minor changes

* updated tests and models

* unused import

* outputs

* Update docs/source/model_doc/resnet.mdx
Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

* added embeddings_size

* Apply suggestions from code review
Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

* conversation

* added push to hub

* test

* embedding_size

* make fix-copies

* resolved conversations

* CI

* changed organization

* minor changes

* CI

* minor changes

* conversations

* conversation

* doc

* tests

* removed unused docstring

* conversation

* removed unused outputs

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

utils/documentation_tests.txt

@@ -31,3 +31,4 @@ src/transformers/models/plbart/modeling_plbart.py
 src/transformers/generation_utils.py
 docs/source/quicktour.mdx
 docs/source/task_summary.mdx
+src/transformers/models/resnet/modeling_resnet.py