Enable federated SPARQL queries per default

[holycrab13]

Start virutoso with the appropriate settings or let the gstore change the settings on the virtuoso after startup Permissions that need to be granted:

grant SPARQL_LOAD_SERVICE_DATA to "SPARQL";
grant SPARQL_SPONGE to "SPARQL";

[manonthegithub]

example of a query:

PREFIX dbo: <http://dbpedia.org/ontology/>

SELECT * WHERE {

  SERVICE <http://dbpedia.org/sparql> { 
    {
      SELECT DISTINCT ?city WHERE {
          ?city a dbo:City .
      } LIMIT 10
    }
  }
}

[manonthegithub]

this can be done in a few ways.

• we can run a script in a separate image (it starts, runs the script and goes down) in docker-compose
• we can try to make our own image based on OpenLink's image which will do it during startup @holycrab13 What do you think is better?

[manonthegithub]

@holycrab13 should work with latest commits... please check :), feel free to reopen in case of problems