Convertor fp16 to fp8 (SDXL or SD1.5 checkpoints) - v1.0 Showcase

Convert your checkpoints to fp8:

- half the size (SDXL 6.9Gb -> 3.5Gb, SD1.5 2.2Gb->1.1Gb)

- faster loading

- reduced video memory usage (a little)

- negligible quality loss (try it to see if it's acceptable for you, I didn't find much difference)