~22% less weight VRAM, lossless: base-3 packing for ternary GGUFs

A new, denser GGUF format called Q2_B3 or "B3S" has been developed for ternary models, offering approximately 22% less weight VRAM. This base-3 packing method is lossless for genuinely ternary models, as it stores the same {-1, 0, +1} states and an f16 block scale. It achieves this by using base-3 packing instead of a general-purpose 2-bit representation, without sacrificing precision. This development was posted on behalf of u/llopresto87.