More log options like priority mask, custom time format

[Ulrich Windl]

At monit 5.22.0 you cannot define a "log priority threshold" that allows reducing the amount of events logged to a file. Also the time format cannot be customized. Currently the time format contains the symbolic time zone, but no year. Depending on various preferences, the user may wish to have the year included in the timestamp, and maybe there's a preference for numeric timezone (like "+0200") over a symbolic timezone (like "CEST"). So letting the use customize the time stamp format seems to be a good idea. Another good idea might be to default to some ISO standard fir the format of the time stamp.

[Tildeslash]

Monit allows to log via syslog, which allows to customize the date format, etc., if needed.

To keep the Monit configuration simple, we'll keep the implementation of logging to a file as is.