Add programatic query of existing languages

[hugolpz]

Replace the hard coded line #48 by a programmatic query.

Rapid Query to get relevant info from LLQS :

SELECT ?lang ?langLabel ?code ( count(DISTINCT ?record) as ?nb ) WHERE {
  ?lang prop:P2 entity:Q4 ; rdfs:label ?langLabel . FILTER (lang(?langLabel) = "en").
  OPTIONAL { ?record prop:P4 ?lang ; prop:P2 entity:Q2 . }
  OPTIONAL { ?lang prop:P13 ?code }
}
GROUP BY ?lang ?langLabel ?code
ORDER BY DESC(?nb)

See also :

• lingua-libre/CommonsDownloadTool#2

[Poslovitch]

The current code in create_datasets.sh seems to be out of date compared to what @mickeybarber showed me on Friday. Let's wait for input from him.