llama: model_loader: add TENSOR_READ_LAZY (#27794)

* llama: model_loader: add TENSOR_GET_ROW_LAZY

* add --tensor-read-lazy

* rename to TENSOR_READ_LAZY

* gen docs

* address comments

src/llama-model.h

@@ -756,6 +756,7 @@ struct llama_model_base : public llama_model {
     const int TENSOR_SKIP;
     const int TENSOR_SKIP_IF_VIRTUAL;
     const int TENSOR_ALLOW_RESHAPE;
+    const int TENSOR_READ_LAZY;
 
     explicit llama_model_base(const llama_model_params & params);
     virtual ~llama_model_base() = default;