[core] add a way to only get members with data

[frabarz]

What's needed is to be able to only get the members from the general list which have at least a row of data in an associated fact table. It's open to discussion if this condition would be using as reference all the measures available, or making this parameter the measure name as reference.
This would require to create a query option for the members endpoint, and a modification on core to change the SQL query generated.