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>
@tiborsimko Good point. Done.