Consider using os_log instead for writing to file

[nirs]

Advantages:

• timestamps
• can view the logs using Console.app
• root not needed to view the log
• we can simplify the logging macros added in #46

Disadvantages:

• using a log file is easier
• does not work when running interactively (e.g. during debugging)
• does not work for testing socket_vmnet, running it from a script and testing the output #99
• may not work when socket_vmnet is run via another program that want to manage its logs (e..g lima, saving logs to ~/.lima/_network/socket_vment*.log

It can work if we add an option to opt-int, which can be used in the launchd service.

Links: https://developer.apple.com/documentation/os/os_log