Core shutdown via API/CLI

[tbaumann]

When shutting down the PI the epaper display just says with the last frame.

But when I shut down the pwnagotchi core via the shutdown method via the web interface it shows a nice shutdown message.

Describe the solution you'd like I would like a way to tell the pwnagotchi core to run pwnagotchi.shutdown() via cli.

Describe alternatives you've considered I guess the daemon stops during the shutdown process. I'm actually not sure yet why this doesn't cause the same shutdown sequence. I guess there is no kill handler.