feature request: Implement activity class for starting the deamon on/off

[slush0]

This is similar to #75; it would be practical to implement activity classes to be able to control the deamon from outside applications, like Automate or IFTTT. Two simple activities "Turn on" and "Turn off" would suffice to setting up pretty complex workflows around ABCore.

If implemented, it is quite straightforward to script #75 even without direct implementation in ABCore.

Thanks for consideration!