Auto create RML from SXW on update

It's a feature request. The main idea is to automatically regenerate a RML file when updating the module if the SXW has change.

The checksum (md5, etc.) of the SXW files would be stored in the RML file as a commented line (or directly in the DB), so when the server update the module, it compare the stored value with the actual checksum of the file. If different then use the SXW to RML tool an upload the RML content to database.