Change log for NIX_SYSTEM

Date Changes
2025-01-22 Added grok pattern to support new structure of "kernel" log.
2025-01-17 Added support for dropped logs of the "Could not load host key" and "Set" actions logs in sshd.
2024-12-26 Updated grok pattern to support new structure of "mail" log.
2024-12-26 Updated grok pattern to support new structure of "mail" log.
2024-11-26 Added support for dropped logs of the "reprocess" action logs in sshd.
2024-10-25 Promoted the parser to default.