BERT (MLM) model integration with uagent to predict the masked words!

[sangramsam]

Hello Team,

Happy to see my last PR being merged. I have been working parallelly on another integration bert-base-uncased which is 2nd most downloaded model on huggingface. I m close to testing and finishing this integration, will try to raise PR asap.

BERT is a transformers model pretrained on a large corpus of English data in a self-supervised fashion. This means it was pretrained on the raw texts only, with no humans labeling them in any way with an automatic process to generate inputs and labels from those texts.

I'd appreciate any guidance or feedback to this integration.