GPU offload policy (#405)

* Adding GPU offload policy

* Minor

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Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>

common/common.h

@@ -143,6 +143,7 @@ struct gpt_params {
     std::vector<std::string> antiprompt; // strings upon which more user input is prompted (a.k.a. reverse prompts)
     std::vector<llama_model_kv_override> kv_overrides;
     std::vector<llama_model_tensor_buft_override> tensor_buft_overrides;
+    std::vector<std::pair<int,int>> offload_policy;
 
     bool lora_init_without_apply = false; // only load lora to memory, but do not apply it to ctx (user can manually apply lora later using llama_lora_adapter_apply)
     std::vector<llama_lora_adapter_info> lora_adapters; // lora adapter path with user defined scale