[SDXL] Allow SDXL LoRA to be run with less than 16GB of VRAM (#4470)
* correct
* correct blocks
* finish
* finish
* finish
* Apply suggestions from code review
* fix
* up
* up
* up
* Update examples/dreambooth/README_sdxl.md
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
* Apply suggestions from code review
---------
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>