Refactor searching text attributes.

* Allow using ApplicationRecord#attribute_matches to search text attributes,
and standardize models on using this instead of duplicating code.

* Remove restrictions that limited wildcard searches to Builders only in various places.

app/models/wiki_page_version.rb

@@ -20,6 +20,8 @@ class WikiPageVersion < ApplicationRecord
         q = q.where("wiki_page_id = ?", params[:wiki_page_id].to_i)
       end
 
+      q = q.attribute_matches(:title, params[:title])
+      q = q.attribute_matches(:body, params[:body])
       q = q.attribute_matches(:is_locked, params[:is_locked])
       q = q.attribute_matches(:is_deleted, params[:is_deleted])