The notfification APIs now use NotificationSpec as their only parameter, which
contains all information (required and optional ones).
We no longer have separate methods and actions for SMS/EMAIL/GENERIC anymore.
The type of notification is important now, not how we received them technically.
- append a string on the control center when the device is charging
- battery status string is no more, welcome battery state enum
- the notification will not be shown when the device is charging, even if the level is below threshold