Add older MMTEB baselines

[orionw]

I was aggregating models for a different project and realized there are a couple of older multilingual baselines we should try. facebook/mcontriever-msmarco (Contriever multilingual) and castorini/mdpr-tied-pft-msmarco (DPR-based with tied encoders). I don't think they're going to be very strong, but they're potentially worth having since they're baselines people may have heard of. Both can be run with sentence-transformers out of the box.

cc @KennethEnevoldsen and @Muennighoff