Zabbix

....I..... [ZBXNEXT-6921] added scripts for upgrading hist tables to pk

* commit 'f3b9848e458867c5b834e4f299944e8e90eb0d37':
  ....I..... [ZBXNEXT-6921] added postgres script for upgrading hist tables to pk
  ....I..... [ZBXNEXT-6921] added oracle script for upgrading hist tables to pk
  ....I..... [ZBXNEXT-6921] added mysql history pk upgrade script