Improve item type db.odbc.select: Return multiple columns (and rows) from SQL ODBC

The idea is to populate SQL results in to multiple dependent items in a single request.

In Zabibix 3.4 introduced

• dependent items functionality (ZBXNEXT-3006) to reduce amount of calls for host metrics gathering.
• JSON item values pre-processing (ZBXNEXT-3863)
  In early version already available ODBC checks
• documented at https://www.zabbix.com/documentation/2.4/ru/manual/config/items/itemtypes/odbc_checks