[DA Beta?] Tag and Category Filters do not Work

[rthaut]

This is also from a user report (like #46), but I'm assuming they are closely related.

With the new URL structure used by thumbnail links, the metadata is probably not being applied to thumbnails, causing tag and category filtering to not work.

Presumably the URL for deviations returned by the APIs is still the old format, but if the DOM is using the new format, then the script cannot "apply" the metadata to the thumbnails (since it has to use the URL to match metadata to thumbnails).

Additionally, the cached metadata is stored/indexed by URL, so that will require some rework as well.

I think the proper solution is going to be to match by the deviation's slug, which is basically the deviation's title and some unique numeric ID appended to that. That should work for both the old and the new URL formats without having to actually check for both formats (thus looping through the metadata twice).

This means that the metadata cache could also be adjusted to just store that slug (rather than the full URL); doing so would not only save a few bytes, but would also prevent the script from having to extract the slug from each URL before applying, thus improving performance a bit. We should increment the IndexedDB version, and then use the UpgradeDB Callback to migrate/modify all existing items.