transformers safetensors llama text-generation llama-2 arxiv:2307.09288 arxiv:1910.09700 conversational base_model:meta-llama/Llama-2-7b-chat-hf base_model:quantized:meta-llama/Llama-2-7b-chat-hf license:apache-2.0 autotrain_compatible text-generation-inference 4-bit region:us