Add TFSpeech2Text (#15113)

* Add wrapper classes

* convert inner layers to tf

* Add TF Encoder and Decoder layers

* TFSpeech2Text models

* Loadable model

* TF model with same outputs as PT model

* test skeleton

* correct tests and run the fixup

* correct attention expansion

* TFSpeech2Text pask_key_values with TF format

docs/source/model_doc/speech_to_text.mdx

@@ -144,3 +144,13 @@ See the [model hub](https://huggingface.co/models?filter=speech_to_text) to look
 
 [[autodoc]] Speech2TextForConditionalGeneration
     - forward
+
+## TFSpeech2TextModel
+
+[[autodoc]] TFSpeech2TextModel
+    - call
+
+## TFSpeech2TextForConditionalGeneration
+
+[[autodoc]] TFSpeech2TextForConditionalGeneration
+    - call