[QEff Finetune]: Refactor the finetune main __call__

[vbaddi]

• Refactor the finetune main api
• Add support to override the PEFT config (yaml/json)
• Add support to validate the correctness of PEFT Config
• Some nit changes

r: 16
lora_alpha: 64
target_modules:
  - q_proj
  - v_proj
  - k_proj
bias: none
task_type: CAUSAL_LM
lora_dropout: 0.1

Command:

python -m QEfficient.cloud.finetune \
    --model_name "meta-llama/Llama-3.2-1B" \
    --lr 5e-4 \
    --peft_config_file "lora_config.yaml"

Using Default LoRA Config:

python -m QEfficient.cloud.finetune \
    --model_name "meta-llama/Llama-3.2-1B" \
    --lr 5e-4