Add DEBERTA-base model for usage in EncoderDecoderModel. #12436
Description
🚀 Feature request
Add DEBERTA-base model as an option for creating an EncoderDecoderModel.
Motivation
Currently only BERT and RoBERTa models can be transformed to a Seq2Seq model via EncoderDecoder class, and for those of use developing DeBERTa models from scratch it would be wonderful to be able to generate a Seq2Seq model from them. Also, the Deberta-base model works much better than BERT and RoBERTa.