Please add extension metadata support to allow for an invisibility option on single foreign tables/views for odata layer

The issue arose from the discussion at

https://developer.jboss.org/message/989502#989502

> Every tables and view I specify is becoming visible in the odata service. Of course I can use GRANT to resctrict access, however, it would be more nice to not export the tables in the odata layer in the first place. Would it be possible to add some kind of per table/view INVISIBLE OPTION for odata, or could I reach the same result in a different way and how would this look like?