Schema extractor needs table owner

The fgldbsch schema extractor requires a -ow option to distinguish different database users/shemas.

Starting with version 2.30, the fgldbsch schema extractor will always use a table owner / schema to select tables from databases where several schemas can hold tables with the same name.

The table owner can be specified with the -ow option, and defaults to the user name passed with the -un option, or to the current database user if no -up option was given. The last case can occur when the database connection information is taken from the FGLPROFILE configuration file, or when the OS user authentication is used.