Adds support to new SDXL dreambooth LoRA training script features + Q…

…OL features (#448)

* support for new script features

* comment about the --caption_column arg

* - fixed typos and added some comments
- added a call to create_repo and removed --push_to_hub tag
- removed xformers install as I think it will likely not work for most users

* remove redundant cell

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Co-authored-by: Linoy <linoy@huggingface.co>