[New Model] VHRED Retrieval model

[NicolasAG]

We already have Dual Encoder retrieval model, but the responses given by Rosemary in Ethics paper seems pretty good. can we quickly add the existing vhred model?

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turns out, according to Rosemary we need the entire repo bcs "Vhred model don't allow interactive interface". But I'm not sure thats a valid reason...