Fix tag ordering in humanized_essential_tag_string.

* Pick the largest character or copyright tags by post count. Previously
  we picked the tags with the longest names, which was nonsensical.

* Remove tag cateogory logic from config file. We can't avoid hardcoding
  some knowledge about tag categories here, so there's no point in trying.

This affects tab titles on post show pages as well as filenames in
downloaded images.

app/presenters/tag_set_presenter.rb

@@ -61,33 +61,22 @@ class TagSetPresenter < Presenter
     end.reject(&:blank?).join(" \n")
   end
 
-  def humanized_essential_tag_string(category_list: TagCategory.humanized_list, default: "")
-    strings = category_list.map do |category|
-      mapping = TagCategory.humanized_mapping[category]
-      max_tags = mapping["slice"]
-      regexmap = mapping["regexmap"]
-      formatstr = mapping["formatstr"]
-      excluded_tags = mapping["exclusion"]
+  def humanized_essential_tag_string(default: "")
+    chartags = tags_for_category("character")
+    characters = chartags.max_by(5, &:post_count).map(&:unqualified_name)
+    characters += ["#{chartags.size - 5} more"] if chartags.size > 5
+    characters = characters.to_sentence
 
-      type_tags = tags_for_category(category).map(&:name) - excluded_tags
-      next if type_tags.empty?
+    copytags = tags_for_category("copyright")
+    copyrights = copytags.max_by(1, &:post_count).map(&:unqualified_name)
+    copyrights += ["#{copytags.size - 1} more"] if copytags.size > 1
+    copyrights = copyrights.to_sentence
+    copyrights = "(#{copyrights})" if characters.present?
 
-      if max_tags > 0 && type_tags.length > max_tags
-        type_tags = type_tags.sort_by {|x| -x.size}.take(max_tags) + ["etc"]
-      end
+    artists = tags_for_category("artist").map(&:name).grep_v("banned_artist").to_sentence
+    artists = "drawn by #{artists}" if artists.present?
 
-      if regexmap != //
-        type_tags = type_tags.map { |tag| tag.match(regexmap)[1] }
-      end
-
-      if category == "copyright" && tags_for_category("character").blank?
-        type_tags.to_sentence
-      else
-        formatstr % type_tags.to_sentence
-      end
-    end
-
-    strings = strings.compact.join(" ").tr("_", " ")
+    strings = "#{characters} #{copyrights} #{artists}"
     strings.blank? ? default : strings
   end