Fixes for mps/Metal: use of seeds, img2img, CodeFormer

 Instance of CUDA out of memory on a low-res batch, even with --opt-split-attention-v1 (found cause) #255

Update cross attention to the newest version

Channels last support

Add --gradio-auth command line argument to enable Gradio authentication

Allows you to pass in Gradio authentication like:
`--auth username:password`
Supports multiple sets of credentials by comma-delimiting, like:
`--auth user1:pass1,user2:pass3`...

Add --hide-ui-dir-config command line flag

changed default cfg_scale to a higher value