[Research] Latent Perceptual Loss (LPL) for Stable Diffusion XL (#11573)
* initial
* added readme
* fix formatting
* added logging
* formatting
* use config
* debug
* better
* handle SNR
* floats have no item()
* remove debug
* formatting
* add paper link
* acknowledge reference source
* rename script
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Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>