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/ban.rb

@@ -44,9 +44,7 @@ class Ban < ApplicationRecord
       q = q.where("user_id = ?", params[:user_id].to_i)
     end
 
-    if params[:reason_matches].present?
-      q = q.reason_matches(params[:reason_matches])
-    end
+    q = q.attribute_matches(:reason, params[:reason_matches])
 
     q = q.expired if params[:expired].to_s.truthy?
     q = q.unexpired if params[:expired].to_s.falsy?