Fix Tokenization + misc fixes (#354)
* fix loggers with multimetric, fix pariwise tokenization + fallback for non-pairwise, add pairwise to vllm, use multiprocess fordataset loading
* fix test + implementation
* finally do the tokenization correctly
* pair_wise -> pairwise
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Co-authored-by: Nathan Habib <30601243+NathanHB@users.noreply.github.com>
