move limit.conf to db.conf

conf/autoload_configs/limit.conf.xml → conf/autoload_configs/db.conf.xml

-<configuration name="limit.conf" description="LIMIT Configuration">
+<configuration name="db.conf" description="LIMIT DB Configuration">
   <settings>
     <!--<param name="odbc-dsn" value="dsn:user:pass"/>-->
   </settings>