WebSearch: fix record numbering for pagination

* Adds the nb_found argument to print_records allowing for a different
  list of records to be printed and number of records found, when we are
  only printing a subset of a total number of records found.

(closes #1762)

Signed-off-by: Nikolaos Kasioumis <nikolaos.kasioumis@cern.ch>
If we need to add a new parameter to an API-like function, then let's add it at the end, otherwise we might break many calls of `print_records()` that site overlays may have used locally.