[Feature] Allow two profile images for performers

[miltuss]

Films/Groups in stash are entitled to two cover images, while performers are only entitled to one profile image!

I would like to use a standard profile image for performers and another NSFW image.

This could be done in different ways:

1 - Mouse Rover on the performer card to display the second image
2 - directional arrow on the card to scroll to the second image
3 - Button on the card to switch from one image to another
...

All these methods of displaying the second image can be offered in the settings to the user and let him choose the one he prefers.

[sleetx]

I like this idea. Having a primary and secondary performer image would allow for various image themes depending on the user's preference. Front/Back, SFW/NSFW, etc.

To do this, we'd need to update "Set Image from File/URL" along with the performer scraper tool. Right now the scraper popup only permits a single image selection from a series of scraped images. What's the best way to modify that UI so a primary and secondary image can be selected?

[DogmaDragon]

Duplicate of #571