A Philadelphia-based organization wants to start a charter school in the Norristown area for children in kindergarten though sixth grade. Stem Enrichment Academy is filling out an application with help from Morgan State University in Baltimore.  Stem Chief Executive Anthony Gordon says three Norristown organizations went to him asking for help in providing alternative education.  The school would stress math, science and technology, and it might be located in the vacant Kennedy-Kenrick High School Building on Johnson Highway.  The Norristown Area School Board will probably vote on the application early next year.