Fix: Add journald log acquisition example for Debian 12 compatibility

[oberator]

Fix: Update acquis.yaml to use journald instead of missing syslog files on Debian 12

📄 Description

On Debian 12 i'm facing the following error:

time="2025-04-28T10:28:07+02:00" level=info msg="Adding file /var/log/auth.log to datasources" type=file
time="2025-04-28T10:28:07+02:00" level=warning msg="No matching files for pattern /var/log/syslog" type=file
time="2025-04-28T10:28:07+02:00" level=warning msg="No matching files for pattern /var/log/traefik/access.log" type=file
time="2025-04-28T10:28:07+02:00" level=info msg="Starting processing data"
time="2025-04-28T10:28:07+02:00" level=warning msg="/var/log/auth.log is a directory, ignoring it." type=file

This pull request updates the documentation (README.md) to address this issue and properly support Debian 12 and newer distributions that use systemd's journald for log management instead of traditional file-based logs like /var/log/syslog and /var/log/auth.log.

Changes made:

• Extended readme.md with a journalctl source configuration example, as recommended by https://docs.crowdsec.net/docs/data_sources/journald/.

🔍 Reason for Change

On Debian 12 and similar systemd-based systems:

• /var/log/syslog and /var/log/auth.log do not exist by default.

• CrowdSec emits warnings about missing files and cannot monitor authentication or system events properly.

• journalctl is the current best-practice for log acquisition.

This update ensures that users of the traefik-crowdsec-stack have clear guidance for configuring log acquisition reliably on modern operating systems.

[psycho0verload]

Unfortunately, it's not that simple. I checked this in the latest instructions, but it's not possible without granting further rights. Since CrowdSec runs in a container and not natively on the server