Zabbix

A.......S. [ZBX-27561] mitigated recurring system errors when editing groups for users or hosts in parallel API requests

* commit 'a5e70a0756d0d5b01f3170e62be46ecaca20689c': (24 commits)
  ........S. [ZBX-27561] removed redundant condition in housekeeper
  .......... [ZBX-27561] fixed duplicate entry error in hgset table by backing up data tables
  ........S. [ZBX-27561] fixed condition in housekeeper
  .......... [ZBX-27561] fixed duplicate entry error in hgset table by backing up data tables
  A......... [ZBX-27561] fixed comments
  A......... [ZBX-27561] removed redundant code and renamed functions to reflect updated behavior
  ........S. [ZBX-27561] fixed host group deletion
  A......... [ZBX-27561] simplified user_ugset userids fetch
  A......... [ZBX-27561] simplified user_ugset userids fetch
  .......... [ZBX-27561] fixed changelog
  .......... [ZBX-27561] fixed changelog
  ........S. [ZBX-27561] added transaction to housekeeper
  A......... [ZBX-27561] removed redundant code and renamed function to reflect updated behavior
  A......... [ZBX-27561] fixed code style
  A......... [ZBX-27561] removed redundant code
  ........S. [ZBX-27561] replaced hgset deletion by server by unlinking hgset from hosts
  ........S. [ZBX-27561] changed housekeeper to clean all sets
  ........S. [ZBX-27561] fixed syntax error in SQL query
  ........S. [ZBX-27561] changed how deleted by housekeeper ugset and hgset numbers are counted
  ........S. [ZBX-27561] implemented ugset and hgset cleanup by housekeeper
  ...

(cherry picked from commit e89296ea5a84cd486eb47cdfcaf81864546ee04f)