Zabbix

A.FG...PS. [ZBXNEXT-6923,ZBXNEXT-6928] added High availability cluster support

Merge in ZBX/zabbix from feature/ZBXNEXT-6923-5.5 to master

* commit 'a1be8e68fcd8f7eef1c7345db0335a4777fd9c4f': (244 commits)
  .D........ [ZBXNEXT-6923] updated changelog entry
  ....I..... [ZBXNEXT-6923] fixed merge
  ....I..... [ZBXNEXT-6923] updated ServerActive parameter for windows agent and agent2
  ........S. [ZBXNEXT-6923] fixed debug log
  .D........ [ZBXNEXT-6923] updated changelog entry
  ........S. [ZBXNEXT-6923] fixed oracle timestamp select
  ...G...... [ZBXNEXT-6923] fixed go linter warnings
  ........S. [ZBXNEXT-6923] added ha discovery data to zabbix[stats]
  ...G...... [ZBXNEXT-6923] fixed Zabbix sender in case of multiple server IP addresses
  .D........ [ZBXNEXT-6923] updated Server and ServerActive parameter description
  ...G...... [ZBXNEXT-6923] fixed agent2 tests
  ...G...PS. [ZBXNEXT-6923] fixed various warnings
  ........S. [ZBXNEXT-6923] fixed warnings, comments
  ...G...PS. [ZBXNEXT-6923] fixed nested externan declarations warning
  ...G...PS. [ZBXNEXT-6923] reduced variable scope
  ........S. [ZBXNEXT-6923] fixed warnings
  ........S. [ZBXNEXT-6923] fixed service timecout calculation
  ........S. [ZBXNEXT-6923] changed zbx_ipc_service_recv() timeout parameter from double to zbx_timespec_t
  ........S. [ZBXNEXT-6923] fixed memory leak, removed redundant code
  ........S. [ZBXNEXT-6923] removed redundant code
  ...