Add TensorFlow implementation of EfficientFormer (#22620)

* Add tf code for efficientformer

* Fix return dict bug - return last hidden state after last stage

* Fix corresponding return dict bug

* Override test tol

* Change default values of training to False

* Set training to default False X3

* Rm axis from ln

* Set init in dense projection

* Rm debug stuff

* Make style; all tests pass.

* Modify year to 2023

* Fix attention biases codes

* Update the shape list logic

* Add a batch norm eps config

* Remove extract comments in test files

* Add conditional attn and hidden states return for serving output

* Change channel dim checking logic

* Add exception for withteacher model in training mode

* Revert layer count for now

* Add layer count for conditional layer naming

* Transpose for conv happens only in main layer

* Make tests smaller

* Make style

* Update doc

* Rm from_pt

* Change to actual expect image class label

* Remove stray print in tests

* Update image processor test

* Remove the old serving output logic

* Make style

* Make style

* Complete test

docs/source/en/model_doc/efficientformer.mdx

@@ -37,7 +37,7 @@ EfficientFormer-L7, obtains 83.3% accuracy with only 7.0 ms latency. Our work pr
 reach extremely low latency on mobile devices while maintaining high performance.*
 
 This model was contributed by [novice03](https://huggingface.co/novice03) and [Bearnardd](https://huggingface.co/Bearnardd).
-The original code can be found [here](https://github.com/snap-research/EfficientFormer).
+The original code can be found [here](https://github.com/snap-research/EfficientFormer). The TensorFlow version of this model was added by [D-Roberts](https://huggingface.co/D-Roberts).
 
 ## Documentation resources
 
@@ -66,3 +66,18 @@ The original code can be found [here](https://github.com/snap-research/Efficient
 
 [[autodoc]] EfficientFormerForImageClassificationWithTeacher
     - forward
+
+## TFEfficientFormerModel
+
+[[autodoc]] TFEfficientFormerModel
+    - call
+
+## TFEfficientFormerForImageClassification
+
+[[autodoc]] TFEfficientFormerForImageClassification
+    - call
+
+## TFEfficientFormerForImageClassificationWithTeacher
+
+[[autodoc]] TFEfficientFormerForImageClassificationWithTeacher
+    - call