Add connection label to queryArgs in connection string

[scherepanov]

vertica-sql-go is setting connection label to fixed string, like vertica-sql-go-1.1.1-21465-1663962464

Please add to connection URL new argument - client label. Should not be hard.

All existing Vertica clients can set connection label, except vertica-sql-go and vsql.

Note that setting connection label by using function set_client_label, after connection already established, does not update DC tables, and cannot be used for audit. Audit is primary goal for this ticket.