Add support for logging to file w/o going through syslog

[xavierba]

Sympa default configuration logs to syslog facility local1.
One needs to configure the local syslogger to have sympa write to, say, /var/log/sympa.log, then restart the syslogger to get any log.
It would be nice to be able to log directly to a file, while still retaining the capability to use a syslogger.

[ikedas]

How about use of log4perl or similar packages?

[xavierba]

log4perl with Log::Dispatch should allow for a lot of flexibility.

[mitar]

I would also prefer if sympa would log to stdout, preferably as JSON.