refactor, lora support and utils for saving and loading

src/pet/utils/__init__.py

@@ -3,3 +3,5 @@
 # module, but to preserve other warnings. So, don't check this module at all
 
 from .config import PETConfig, PETType, PromptLearningConfig, TaskType
+from .other import bloom_model_postprocess_past_key_value, shift_tokens_right
+from .save_and_load import get_pet_model_state_dict, set_pet_model_state_dict