compresslog: replace standard logger with a handrolled logger to syslog

compresslog: replace standard logger with a handrolled logger to syslog

The standard Python logger is great, but it loads all the possible
loggers into memory, costing ~5MB in RAM per instance of compresslog.

This simplistic implementation loses some features, specifically the
nice "log stacktraces to syslog", but that is a secondary consideration
to avoiding OMM killer visits.