GOsxNetworkMonitor: Add network monitor backend for OS X
OS X backend to GNetworkMonitor, using sysctl and PF_ROUTE socket.
Tested on Ventura 13.5.2
Fixes: #1326
OS X backend to GNetworkMonitor, using sysctl and PF_ROUTE socket.
Tested on Ventura 13.5.2
Fixes: #1326