Syslogd less verbose logging with rfc5424

[Pavel Timofeev]

Hello, dear community!

There was a great work to bring rfc5424 date format to syslogd(8). See
https://svnweb.freebsd.org/base?view=revision&revision=332510

I've been using it on CURRENT since it was imported.
I'm happy I can finally get syslog messages with high time precision
w/o installing rsyslog or another syslog implementation.
The thing I really don't like is that syslogd puts severity and
priority to log files next to timestamp.
In my opinion severity and priority is not needed in 99% of cases,
only in debugging corner cases. While high precision timestamp is the
main thing what people like rfc 5424 for. This is just my opinion.
So for "-O rfc5424" I'd like to have the same behavior as for rfc
3164, i. e. do not log severity and priority by default and if needed
use '-v' option to enable those. But it was decided and documented
that  '-v' won't have any effect for rfc 5425
https://svnweb.freebsd.org/base?view=revision&revision=335862

The first thing I'd like to suggest is to make rfc 5424 logging the
same way as for rfc 3164, i. e. make '-v' option work the same.
If community is not agree with me, I'd like to suggest another thing:
have another option/flag for syslogd(8) to disable severity and
priority logging if one use rfc 5424.