Write w2v-BERT pretraining recipe

[cbalioglu]

As the second recipe after NLLB, write the w2v-BERT (and wav2vec2) pretraining recipe for users to check out. This will likely branch to several subtasks once we start working on it.

[seastar105]

@cbalioglu any progress on pre-train or finetune w2v bert recipe?

[kdcyberdude]

Hi @cbalioglu, Any update on this... We want to do the continual training of w2v-bert on specific Indic low-resource languages on audio-only data. Any suggestion on how should we approach this?