WebSearch: fix for record numbering in pagination

* Adds optional `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) (PR #1763)

Signed-off-by: Nikolaos Kasioumis <nikolaos.kasioumis@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>