Fix it being possible to reject approved BURs, or to re-reject already
rejected BURs.
Rejecting an approved BUR wouldn't revert the aliases/implications, but
it would change the BUR's status to rejected.
* When creating an artist by clicking the '?' next to the artist tag in
the tag list, prefill the new artist form by finding the artist's last
upload and fetching its source data.
Previously we filled the urls with the source of the artist's last
upload, which was wrong because it was usually a direct image URL (#3078).
* Fix the other names field not escaping spaces within names to underscores.
* Fix the other names field being potentially prefilled with duplicate names.
Refactor the /related_tags.js call so that when the "Related tags"
button is clicked, it only replaces the columns that actually changed,
not the entire related tags section.
This avoids rebuilding the Recent / Frequent / Translated Tags / Artist
columns every time the "Related tags" button is clicked.
* Move the limit:<n> / order:random metatag parsing from the controller
to the post set.
* Introduce `Tag.has_metatag?` and use it to parse these metatags
instead of using a regex (#2894).
* On posts, automatically trigger "Fetch source data" when clicking the
Edit tab, instead of triggering the artist finder button. This way we
find both the artist and the translated tags in one ajax call.
* Remove the "Artist" finder button next to the source field. This isn't
necessary given that "Fetch source data" finds the artist itself.
* Remove the /artists/finder.json API endpoint. This is no longer used
after removing the "Artist" finder button.
Make <role>_only methods check the role first and ip bans last. This
avoids hitting the database for anonymous users, since they'll always
fail the is_<role>? check before the ip check.
Instead of calling /sources.json and rendering the "Fetch source data"
box client-side in Javascript, call /sources.js so we can render the
html server-side.
* On the /uploads/new page, instead of just showing a "This post has
probably already been uploaded" message, show the actual thumbnails of
posts having the same source as what the user is trying to upload.
* Move the iqdb results section up top, beside the related posts section.
Also makes it so that using the bookmarklet always triggers async upload
preprocessing. Before it was only triggered when the source passed a
dupe check, but that check was inaccurate (#3873).
