Zabbix

A......... [ZBX-20263] prevented the ability to link two or more templates with matching item keys to a host or template

* commit 'e6ad1309f146ef5301b79c0e5ca3503d0e0fdff9':
  A......... [ZBX-20263] simplified code
  .D........ [ZBX-20263] fixed ChangeLog entry
  A......... [ZBX-20263] prevented the ability to create two items with the same key_ on different templates that are linked to the same host
  A......... [ZBX-20263] fixed error message for duplicate inherited item key_
  A......... [ZBX-20263] fixed validation for items with dupblicate key_
  A......... [ZBX-20263] fixed possibility to link templates with matchin item keys with less API requests.
  A......... [ZBX-20263] reversed previous commit 66e6e535143
  A......... [ZBX-20263] removed possibility to link host or template to two templates with the same item key