Rename Artist#find_all_by_url to url_matches and drop previous
url_matches method, along with find_artists and search_for_profile.
Previously find_artists tried to lookup the url, referer url, and profile
url in turn until an artist match was found. This was wasteful, because
the source strategy already knows which url to lookup (usually the profile
url). If that url doesn't find a match, then the artist doesn't exist.
* 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.
The api data is unavailable when we can't scrape the uuid, either
because the work is deleted or because the work is actually a sta.sh
upload and we weren't given the sta.sh page in the referer url.
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.
* Replace AnonymousUser null object with a readonly, unpersisted User object.
* Default always_resize_images to true (previously it was true for
anonymous users, but false for new members).
* Default comment_threshold to -1 for anonymous users (previously it was
0 for anonymous but -1 for new members).
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.
* `legacy_normalize` came from c6012535, which is no longer a problem.
* `normalize_for_search` is only used for "[mass edit]" links
in artist entries. These links are a shortcut for performing a
`-artist_name source:<artist_url> -> artist_name` mass edit to tag
untagged artists, but this won't work for most sites these days.
