llama : add inference support and model types for T5 and FLAN-T5 model families
llama : add new API functions to support encoder-decoder models: llama_encode(), llama_model_has_encoder(), llama_model_decoder_start_token()
common, llama-cli : use new API functions to support encoder-decoder models
convert-hf : handle shared token embeddings tensors in T5Model
convert-hf : handle SentencePiece BPE tokenizer in T5Model (for Pile-T5 models)
convert-hf : add MT5ForConditionalGeneration and UMT5ForConditionalGeneration to architectures supported by T5Model