Update: Use Delete Column for resources

coscine/issues#1321

src/SemanticSearch/Clients/RdfClient.cs

@@ -196,7 +196,8 @@ namespace Coscine.SemanticSearch.Clients
 
             var query = $@"{{ 
                 GRAPH ?g {{
-                    ?g a {Uris.ORG_ORGANIZATIONAL_COLLABORATION}
+                    ?g a {Uris.ORG_ORGANIZATIONAL_COLLABORATION} .
+                    ?g <{Uris.COSCINE_PROJECT_DELETED}> ""false""^^xsd:boolean .
                 }}
             }}";
 
@@ -228,6 +229,7 @@ namespace Coscine.SemanticSearch.Clients
             var query = $@"{{ 
                 ?p a {Uris.ORG_ORGANIZATIONAL_COLLABORATION} .
                 ?p {Uris.DCAT_CATALOG} ?g .
+                ?g <{Uris.COSCINE_RESOURCE_DELETED}> ""false""^^xsd:boolean .
             }}";
 
             using var result = _connector.QueryWithResultSet("SELECT COUNT(?g) AS ?count " + query);