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/controllers/uploads_controller.rb

@@ -60,7 +60,7 @@ class UploadsController < ApplicationController
 
   def default_includes(params)
     if ["json", "xml"].include?(params[:format])
-      [:uploader]
+      []
     else
       [:uploader, {post: [:uploader]}]
     end