add placenames count query

Author: valentinedwv

backend/examples/facetsearch/all_count_placenames.rq

@@ -0,0 +1,11 @@
+
+PREFIX schema: <http://schema.org/>
+PREFIX sschema: <https://schema.org/>
+
+SELECT DISTINCT   ?name (count(?subj) as ?datasetcount)  (count(?name) as ?count) WHERE {
+ ?subj sschema:spatialCoverage ?placenames_node .
+      ?placenames_node sschema:name ?name .
+}
+group by ?name
+ORDER BY DESC(?count)
+