(PA-3491) Add newsyslog config for pxp-agent
(PA-3491) Add newsyslog config for pxp-agent

OS X uses newsyslog to rotate log files. By default it's configured to
run every 30 minutes. Add a configuration file for the pxp-agent log
file, similar to the logrotate one.

The configuration file does the following:
- rotate logs every day
- keep a maximum of 30 files
- send SIGUSR2 to pxp-agent after rotating
- don't write specific headers when rotating (may interfere with
  external log analysis tools)

puppetlabs/pxp-agent,puppetlabs/pxp-agent,puppetlabs/pxp-agent