Wav2Vec2 Pretraining (#11306)

* Working quantizer forward

* Working quantizer forward

* Clean up unused model parts, test reproducibility

* Working quantizer forward

* Clean up unused model parts, test reproducibility

* Remove custom outputs from the shared ones

* correct conversion

* correct bug

* add first pretrain script

* save intermediate

* static shapes

* save intermediate

* finish first pretrain script version

* more refactor

* remove wanddb

* refactor more

* improve test

* correct perplexity compute bug

* finish model implementation

* add to docs

* finish docs

* finish pretraining script

* finish pretraining script

* remove wandb

* finish PR for merge

* finish config

* finish

* make deepspeed work

* Apply suggestions from code review

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

* apply suggestions

* fix flaky test

Co-authored-by: patrickvonplaten <patrick.v.platen@gmail.com>
Co-authored-by: Lysandre Debut <lysandre@huggingface.co>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

docs/source/model_doc/wav2vec2.rst

@@ -79,3 +79,10 @@ Wav2Vec2ForCTC
 
 .. autoclass:: transformers.Wav2Vec2ForCTC
     :members: forward
+
+
+Wav2Vec2ForPreTraining
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.Wav2Vec2ForPreTraining
+    :members: forward