Add automatically provenance to imported URI

[jmvanel]

Add automatically provenance to imported URI
This concerns both URL's loaded by /display pages and /load-uri service .
There are two ways:

1. add in /display in expert mode a visual item for the focus URL indicating the Graph(s) URI's of the triples (either in the header or for each triple)
2. introduce a redondance in the database, by adding rdfs:isDefinedBy triples: see below

adding rdfs:isDefinedBy triples via e.g.

<U1> rdfs:isDefinedBy <http://data.origin.org/dump.ttl> .

This can also be added a posteriori by a SPARQL Update, given the structure of the SF database:

prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
INSERT {
  GRAPH ?G {
    ?S rdfs:isDefinedBy ?G .
  }
}
WHERE {
  GRAPH ?G {
    ?S ?P [] .
  }
}