[LoRA Attn Processors] Refactor LoRA Attn Processors (#4765)
* [LoRA Attn] Refactor LoRA attn
* correct for network alphas
* fix more
* fix more tests
* fix more tests
* Move below
* Finish
* better version
* correct serialization format
* fix
* fix more
* fix more
* fix more
* Apply suggestions from code review
* Update src/diffusers/pipelines/stable_diffusion/pipeline_onnx_stable_diffusion_img2img.py
* deprecation
* relax atol for slow test slighly
* Finish tests
* make style
* make style
