macOS package: fdbmonitor output is being lost

On Linux, we run fdbmonitor with the --daemonize flag, which causes it to log to syslog. On macOS, we do not use the --daemonize flag (and I'm not immediately sure why), which results in output going to stderr. As far as I can tell, it doesn't seem that we are capturing stderr anywhere, so this logging output is being lost.

Start at the macOS package's fdbmonitor entry point and trace where its stderr output is handled. Determine how the package should capture or route that output, then verify that fdbmonitor logs are no longer lost on macOS.

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