transformers gguf mergekit merge arxiv:2306.01708 base_model:anthracite-org/magnum-v2-12b base_model:merge:anthracite-org/magnum-v2-12b base_model:nothingiisreal/MN-12B-Celeste-V1.9 base_model:merge:nothingiisreal/MN-12B-Celeste-V1.9 endpoints_compatible region:us conversational