Airplane Mode quick button

[mremski]

The addition of an "Airplane Mode" toggle button that effectively does "ifconfig down" on all physical interfaces would be a quick way to disable all external network connections. It allows proceses using localhost to function, but will prevent any application from phoning home.
Discussed in this thread on discourse:
https://discourse.trueos.org/t/set-so-even-et-cant-phone-home/2481