API: remove various associated fields included by default.

Remove various associated fields that were included by default on
certain endpoints. API users can use the only param to include the
full association if they need these fields.

* /artists.json: urls.
* /artist_urls.json: artist.
* /comments.json: creator_name and updater_name.
* /notes.json: creator_name.
* /pools.json: creator_name.
* /posts.json: uploader_name, children_ids, pixiv_ugoira_frame_data.
* /post_appeals.json: is_resolved.
* /post_versions.json: updater_name.
* /uploads.json: uploader_name.

app/models/comment.rb

@@ -24,8 +24,6 @@ class Comment < ApplicationRecord
     :body => ->(user_name) {"@#{creator.name} mentioned you in a \"comment\":/posts/#{post_id}#comment-#{id} on post ##{post_id}:\n\n[quote]\n#{DText.extract_mention(body, "@" + user_name)}\n[/quote]\n"}
   )
 
-  api_attributes including: [:creator_name, :updater_name]
-
   module SearchMethods
     def deleted
       where("comments.is_deleted = true")
@@ -155,14 +153,6 @@ class Comment < ApplicationRecord
     select { |comment| comment.visibility(user) == :visible }
   end
 
-  def creator_name
-    creator.name
-  end
-
-  def updater_name
-    updater.name
-  end
-
   def delete!
     update(is_deleted: true)
   end