Zabbix

.......... [DEV-2604] refactored dependent item tests; introduced test data helper

* commit '001c85d3cf8a2f190f2eb3708dce9565f58f4b85':
  .......... [DEV-2604] improved code style
  .DF....... [DEV-2604] improved code style, added function descriptions; re-arranged created objects to target separate groups of tests
  .......... [DEV-2604] simplified dependent item API tests; fixed inability to parse item reference with specified template or host
  .......... [DEV-2604] improved generation of the fixture data for API tests; enabled back depentent item test
  .......... [DEV-2604] fixed accidental re-assignment of hostid for discovered hosts; removed debug function
  .......... [DEV-2604] transferred progress from older branch