Zabbix

.........T [ZBX-19864] fixed preprocessing of "Checkpoint sync time" item, fixed the regex in preprocessing in the "Ping time" item, fixed SQL request in the "Get transactions" item in "DB PostgreSQL" template

Merge in ZBX/zabbix from feature/ZBX-19864-5.4 to release/5.4

* commit '35f24d3797e16ccfbc2fb5a92bdc7616da96d019':
  .........T [ZBX-19864] README.md edited online with Bitbucket
  .........T [ZBX-19864] fixed the regex in preprocessing in the "Ping time" item, fixed SQL request in the "Get transactions" item
  .........T [ZBX-19864] fixed preprocessing of "Checkpoint sync time" item in "DB PostgreSQL" template