Change log for NIX_SYSTEM

Date Changes
2025-11-17 - Enhanced grok pattern to map the NetworkManager, CROND, and vsftpd processes to `metadata.product_event_type` UDM field.
2025-11-14 Added grok pattern to support new structure of logs from the `syslog` source path.
2025-11-06 Added GROK pattern to support new structure of logs.
2025-10-31 Updated grok pattern to support new structure of logs in the legacy backward compatibility code.
2025-10-30 Enhanced GROK pattern to support new pattern of logs.
2025-10-13 Added grok pattern to map the following fields in the legacy backward compatibility code.
- target.ip: Newly mapped `DstIP` raw log field with `target.ip` UDM field.
- target.port: Newly mapped `DstPort` raw log field with `target.port` UDM field.
- principal.ip: Newly mapped `SrcIP` raw log field with `principal.ip` UDM field.
- principal.port: Newly mapped `SrcIP` raw log field with `principal.port` UDM field.
2025-10-10 - Added a grok pattern to parse logs from the `syslog` source path in JSON format.
2025-09-09 - target.user.userid: Added grok pattern to remove mapping of the partial value of `username` from the `target.user.userid` UDM field and mapped the complete value of `username` instead.
2025-09-08 Added a grok pattern to support new structure of logs.
- metadata.product_event_type: Newly mapped `process` raw log field with `metadata.product_event_type` UDM field.
- principal.process.pid: Newly mapped `process_id` raw log field with `principal.process.pid` UDM field.
2025-08-26 - Added a grok pattern to parse logs from the `syslog` source path in JSON format.
2025-06-30 Updated grok pattern to support new structure of "syslog" logs.
2025-04-28 intermediary.hostname
2025-03-11 Added grok pattern to support new schema structure of "kernel" logs.
2025-02-11 Updated grok pattern to support new structure of "syslog" logs.
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.