TF implementation of RegNets (#17554)

* chore: initial commit

Copied the torch implementation of regnets and porting the code to tf step by step. Also introduced an output layer which was needed for regnets.

* chore: porting the rest of the modules to tensorflow

did not change the documentation yet, yet to try the playground on the model

* Fix initilizations (#1)

* fix: code structure in few cases.

* fix: code structure to align tf models.

* fix: layer naming, bn layer still remains.

* chore: change default epsilon and momentum in bn.

* chore: styling nits.

* fix: cross-loading bn params.

* fix: regnet tf model, integration passing.

* add: tests for TF regnet.

* fix: code quality related issues.

* chore: added rest of the files.

* minor additions..

* fix: repo consistency.

* fix: regnet tf tests.

* chore: reorganize dummy_tf_objects for regnet.

* chore: remove checkpoint var.

* chore: remov unnecessary files.

* chore: run make style.

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

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

* chore: PR feedback I.

* fix: pt test. thanks to @ydshieh.

* New adaptive pooler (#3)

* feat: new adaptive pooler

Co-authored-by: @Rocketknight1

* chore: remove image_size argument.

Co-authored-by: matt <rocketknight1@gmail.com>

Co-authored-by: matt <rocketknight1@gmail.com>

* Empty-Commit

* chore: remove image_size comment.

* chore: remove playground_tf.py

* chore: minor changes related to spacing.

* chore: make style.

* Update src/transformers/models/regnet/modeling_tf_regnet.py

Co-authored-by: amyeroberts <aeroberts4444@gmail.com>

* Update src/transformers/models/regnet/modeling_tf_regnet.py

Co-authored-by: amyeroberts <aeroberts4444@gmail.com>

* chore: refactored __init__.

* chore: copied from -> taken from./g

* adaptive pool -> global avg pool, channel check.

* chore: move channel check to stem.

* pr comments - minor refactor and add regnets to doc tests.

* Update src/transformers/models/regnet/modeling_tf_regnet.py

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

* minor fix in the xlayer.

* Empty-Commit

* chore: removed from_pt=True.

Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
Co-authored-by: matt <rocketknight1@gmail.com>
Co-authored-by: amyeroberts <aeroberts4444@gmail.com>
Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>

docs/source/en/index.mdx

@@ -267,7 +267,7 @@ Flax), PyTorch, and/or TensorFlow.
 |             RAG             |       ✅       |       ❌       |       ✅        |         ✅         |      ❌      |
 |            REALM            |       ✅       |       ✅       |       ✅        |         ❌         |      ❌      |
 |          Reformer           |       ✅       |       ✅       |       ✅        |         ❌         |      ❌      |
-|           RegNet            |       ❌       |       ❌       |       ✅        |         ❌         |      ❌      |
+|           RegNet            |       ❌       |       ❌       |       ✅        |         ✅         |      ❌      |
 |           RemBERT           |       ✅       |       ✅       |       ✅        |         ✅         |      ❌      |
 |           ResNet            |       ❌       |       ❌       |       ✅        |         ❌         |      ❌      |
 |          RetriBERT          |       ✅       |       ✅       |       ✅        |         ❌         |      ❌      |

docs/source/en/model_doc/regnet.mdx

@@ -27,7 +27,8 @@ Tips:
 - One can use [`AutoFeatureExtractor`] to prepare images for the model.
 - The huge 10B model from [Self-supervised Pretraining of Visual Features in the Wild](https://arxiv.org/abs/2103.01988), trained on one billion Instagram images, is available on the [hub](https://huggingface.co/facebook/regnet-y-10b-seer)
 
-This model was contributed by [Francesco](https://huggingface.co/Francesco).
+This model was contributed by [Francesco](https://huggingface.co/Francesco). The TensorFlow version of the model
+was contributed by [sayakpaul](https://huggingface.com/sayakpaul) and [ariG23498](https://huggingface.com/ariG23498).
 The original code can be found [here](https://github.com/facebookresearch/pycls).
 
 
@@ -45,4 +46,15 @@ The original code can be found [here](https://github.com/facebookresearch/pycls)
 ## RegNetForImageClassification
 
 [[autodoc]] RegNetForImageClassification
-    - forward
+    - forward
+
+## TFRegNetModel
+
+[[autodoc]] TFRegNetModel
+    - call
+
+
+## TFRegNetForImageClassification
+
+[[autodoc]] TFRegNetForImageClassification
+    - call