OAK-1914 - hardwire driver class name for Oracle, add Ora JDBC as embedded for now

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1606820 13f79535-47bb-0310-9956-ffa450edef68
OAK-1914 - fix code that writes truncated JSON into char column to work with smaller Oracle char column

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1606823 13f79535-47bb-0310-9956-ffa450edef68