Convert direct image links to page links in artist tooltips.

[hdk5]

This is primarily about https://i.pximg.net/img-original/img/ links, which contain enough information to convert them to the page URLs. The other that immediately come to mind are:

• https://c.fantia.jp/uploads/post/file/
• https://static1.e621.net/data/
• https://*.gelbooru.com/images/

There may be many others, and since danbooru doesn't return converted url in api, those have to be handled client-side. I think most users, including me, would be happy with just pixiv though.

[7nik]

Seem this logic can be extracted from the Danbooru sources. Though, I'm not familiar with Ruby at all.

[7nik]

I've pushed implementation to the branch feat101, will merge it later. Among the top 30 domains, I've added ones where normalization is possible, is needed, and amount of posts is sufficient. If you want other domains, PR is welcome - adding them should straightforward.