Integrate meta-seconorth-distro/add_syslogging_format_compatibility

Commit: seco-ne/yocto/layers/meta-seconorth-distro@8296cfb8

distro: make syslogging message format compatible with Rocko

With the switch to syslog-ng the default format for file-based logs - esp. /var/log/messages - was changed considerably compared to our previous Yocto versions, e.g.

• severity and PID fields were removed
• several severity levels were no longer logged to /var/log/messages (both unimportant like "debug", but also important like "err"
• messages from several several facilities were no longer logged to /var/log/messages

This patch changes the output for file-based logs and the filter for /var/log/message back to a similar format and contents as provided with our previous Yocto versions (in particular Rocko) to provide compatiblity for customers already using /var/log/messages.