add finetuner_no_trainer

[Dominic789654]

Add the finetuner without trainer api, mainly src/lmflow/pipeline/finetuner_no_trainer.py and corresponding scripts/run_finetune_no_trainer.sh.
For the switch between finetuner and finetuner_no_trainer, you need to change examples/finetune.py line 36. I think there should be a better way to do the switch.

Currently, it can run with the run_finetune_no_trainer.sh successfully.