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>