A blacklist setting that checks against PTR rather than/in addition to file tags

[Zweibach]

A setting for file blacklist to check its list against PTR (and other remote repositories) tags. Should also apply to whitelist and work in both directions so to speak.

Discard if x tag on file unless y tag on PTR.
Discard if x tag on PTR unless y tag on file.
Etc.

There's probably some special considerations that might have to be taken into account due to how unreliable PTR tags can be at times, but it feels like a function that could work well when parsing from sites with bad tagging. Just have to hope the images have been tagged well enough for them to be filtered though that's a separate issue.