Add 16:9 Aspect Ratio

With more aspect ratios (like 16:9), we avoid the need for other software and add more time-wasting steps to re-process the image just to expand it to this aspect ratio. It also avoids the need to upscale just to crop it to the desired aspect ratio. If I like the full image generated by Civitai, I do not want to crop any of it. Just make it the right fit the first time it’s generated. Thank You