[SDXL] Partial diffusion support for Text2Img and Img2Img Pipelines (#4015)
* diffusers#4003 - initial implementation of max_inference_steps
* diffusers#4003 - initial implementation of max_inference_steps and first_inference_step for img2img
* diffusers#4003 - use first_inference_step as an input arg for get_timestamps in img2img
* diffusers#4003 Do not add noise during img2img when we have a defined first timestep
* diffusers#4003 Mild updates after revert
* diffusers#4003 Missing change
* Show implementation with denoising_start and end
* Apply suggestions from code review
* Update src/diffusers/pipelines/stable_diffusion_xl/pipeline_stable_diffusion_xl.py
Co-authored-by: Pedro Cuenca <pedro@huggingface.co>
* move to 0.19.0dev
* Apply suggestions from code review
* add exhaustive tests
* add docs
* finish
* Apply suggestions from code review
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
* make style
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Co-authored-by: bghira <bghira@users.github.com>
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>
Co-authored-by: Pedro Cuenca <pedro@huggingface.co>
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>