AP mode does not activate on the fly when all networks are removed

[MoffKalast]

Not sure if this is viable to implement, but it would be great if AP mode started in the case when:

• pifi had previously set networks and connected to one

• all networks are manually removed

Since otherwise the Pi needs to be restarted by unplugging power to be able to make any kind of connection again.

[MoffKalast]

Partially solved by the rescan command, but would need to be integrated into the remove command to check if all networks are gone.