journald: T9183: stop forwarding journal entries to syslog

rsyslog reads the journal directly through imjournal (rsyslog.conf.j2 loads
it alongside imuxsock), so journald forwarding the same entries to /dev/log
delivers every non-kernel message twice. Both copies land in /var/log files
and go to every remote syslog target, differing only in PID formatting.

Ship the setting as a journald drop-in here rather than as a full
journald.conf in vyos-build, so the image carries only the settings VyOS
actually overrides. MaxLevelSyslog=debug comes across from that file; the
rest of it was commented-out systemd defaults.

Tested on a live 2026.09.11 router: with the drop-in in place a single
logger event produces one entry, remote targets receive one copy, and
kernel messages (imklog) and HAProxy's own socket are unaffected.

0 files changed, 0 insertions, 0 deletions