Feat: customize diffOutputPath detail

[HOUCe]

Hey guys, thanks for the great work of cypress-image-snapshot.

I have a little improvement(if it is) to suggest, blew is my case:
I've developed a NodeJS service based on Cypress and cypress-image-snapshot. In my project, I provided a platform to show reports details including diff images which cypress-image-snapshot produced of course. So I need to customized the reports content like:

See diff for details: https://XXX.XXX.com/diff_image.png

but not a hard coded abs path:

See diff for details: /XXX/XXX/diff_image.png

which should be：

in my case.

So I need a resolveDiffOutputPath function to customize the command details.

If it is ok, I will update docs as well, waiting for your feedback, thanks in advance!