Support for CosXL/CosXL Edit

[rmatif]

Would be great if someone could implement cosxl and cosxl edit!

At first glance, this would require implementing the Cosine-Continuous EDM VPred schedule, currently, the master branch produces garbage images with the existing scheduler when trying to inference with cosxl

cosxl edit might require additional work, but I believe it's worth it since it enables zero-shot image editing while maintaining consistency.

Example Image to motivate