Add Tiled Upscaling support

[minsky91]

It would be great to have a tiled diffusion feature equivalent to MultiDiffusion or SD Upscale in Automatic / Forge, for upscaling large resolution images. Should you decide to implement it, please check out how it's done in Forge's SD Upscale , it's done particularly well there: fast, memory-efficient and with a minimum artifacts in the output. I place now my hopes on StableSwarmUI, since the Forge project looks abandoned.