Add upscaling guide

[moyevka]

An all-round useful addition to the site would be a guide on upscaling images using good ol' all-FOSS ESRGAN. Guide should be two parts, covering upscaling basic screenshots (i.e. from console outputs), then once the texmod addon is finalised, upscaling in-game textures.

Include links to chaiNNer, possibly mention Cupscale for ease of use, and of course, the Upscale Wiki Model Database.

edit:
chaiNNer is hard to use! go with upscale!

edit 2:
We should also talk about models that do not necessarily focus on upscaling, such as the antialiasing model (the third one listed here is said to be good), fixing dithering, etc.
We should also look up models here.

[moyevka]

going back to this: cupscale has been long deprecated and may not work on modern setups - i personally can't get my old cupscale setup to work ever since i moved to a 40-series GPU, and even before that there were multiple issues with old model versions and various versions of cupscale

chaiNNer is likely the way forward, despite its added complexity of use (and it's quite a lot! especially for people not used to working with nodes) it is properly supported and still updated (most recently in late april)

[originalnicodr]

I haven't really followed the whole upscaling field, but maybe it would also be worth mentioning NVIDIA-Ansel-AI-Enhancer and Topaz Gigapixel for completeness sake.