Zabbix

...G...PS. [ZBXNEXT-297] added remote command execution via active checks

Merge in ZBX/zabbix from feature/ZBXNEXT-297-6.5 to master

* commit '5e7e67766870a55c7fa1e6a0879309faff35ef07': (36 commits)
  ...G...... [ZBXNEXT-297] fixed warnings
  ...G...... [ZBXNEXT-297] fixed client plugin cleanup
  ...G...... [ZBXNEXT-297] added output error in the case of command queueing error
  ...G...... [ZBXNEXT-297] refactored command result storing
  ...G...... [ZBXNEXT-297] fixed coding style
  ...G...... [ZBXNEXT-297] check for non-empty commands vector before calling process_active_commands
  ...G...... [ZBXNEXT-297] simplified command/result vector cleanup
  .......PS. [ZBXNEXT-297] fixed multiple result
  ...G...... [ZBXNEXT-297] simplified command registry cleanup
  .......PS. [ZBXNEXT-297] renamed variable
  ...G...PS. [ZBXNEXT-297] removed limitation of command results buffer in Agent2
  ...G...PS. [ZBXNEXT-297] fixed Jenkins warnings
  ...G...PS. [ZBXNEXT-297] fixed c code after code review
  ...G...... [ZBXNEXT-297] don't perform command cleanup on removed clients
  .......PS. [ZBXNEXT-297] refactored active command result waiting loop
  .......PS. [ZBXNEXT-297] updated error message when trying to use active remote commands with 1 trapper
  ...G...PS. [ZBXNEXT-297] modified integration test2
  ...G...PS. [ZBXNEXT-297] modified integration test
  ...G...PS. [ZBXNEXT-297] fixed integration test
  ...G...PS. [ZBXNEXT-297] added commands cleanup
  ...