Zabbix

...G...... [ZBX-20586] reduced agent2 memory usage with openssl

Merge in ZBX/zabbix from feature/ZBX-20586-5.0 to release/5.0

* commit 'db18c66e1e62a5064bc2b309fc7664a45bf25445':
  .D........ [ZBX-20586] added changelog entry
  ...G...... [ZBX-20586] free tls C resources when closing tls connection on agent2