[logback-user] DBNameResolver

Merritt: DBAppenderBase isn't in the loop, but has the event id column name(EVENT_ID) coded into it and doesn't use the DBNameResolver. The event id column name is needed when they create the prepared statement in DBAppenderBase and the database supports getGeneratedKeys. Maybe adding an abstract "getEventIdCol" in DBAppenderBase and implementing it in DBAppender(which has the DBNameResolver). Roy