Zabbix

A......... [DEV-4925] added strict validation for 'filter' and 'search' fields in host.get api

* commit '5ab6a1c6aa7d147a71520c5fff05f8d69cfe3985':
  A......... [DEV-4925] added virtual fields support for host.get api filter field
  A......... [DEV-4925] improved code style for host.get filter and search validation
  A......... [DEV-4925] added strict validation for 'filter' and 'search' fields in host.get api