e621: support "lore" tag category

[feffy380]

Is your feature request related to a problem? Please describe

e621 has a lore tag category with id=8 (see https://e621.net/help/api under Tags > Categories). Grabber doesn't recognize this category, so it can't be used in filenames or when saving tags to log files. Additionally, even though they show up as general tags in the interface (no color highlighting), they do not get included in the tag list unless you use %all%.

Describe the solution you'd like

Lore tags should be accessible as %lore% similar to other categories.

Describe alternatives you've considered

The only alternative is to use %all%, which sacrifices the ability to arrange/filter tags by category

[Bionus]

Fine by me 😄 Surprised nobody requested it earlier, given it seems those were added back in 2020.