add OnnxStableDiffusionUpscalePipeline pipeline (#2158)
* [Onnx] add Stable Diffusion Upscale pipeline
* add a test for the OnnxStableDiffusionUpscalePipeline
* check for VAE config before adjusting scaling factor
* update test assertions, lint fixes
* run fix-copies target
* switch test checkpoint to one hosted on huggingface
* partially restore attention mask
* reshape embeddings after running text encoder
* add longer nightly test for ONNX upscale pipeline
* use package import to fix tests
* fix scheduler compatibility and class labels dtype
* use more precise type
* remove LMS from fast tests
* lookup latent and timestamp types
* add docs for ONNX upscaling, rename lookup table
* replace deprecated pipeline names in ONNX docs
