Feature request: Please add MQTT Messages for Activity status

[hdiessner]

Hi and first of all, thank you for your excellent work!
Could you please add the "Activity status" (the activityStatus represents the following states: 0 = Hub is off, 1 = Activity is starting, 2 = Activity is started, 3 = Hub is turning off) as MQTT messages?

Similar to the work in the node-red Node for Harmony: https://flows.nodered.org/node/node-red-contrib-harmony

Use case / benefit: If you already send a MQTT message when an activity is starting, you could trigger other devices (like turn on a power switch) before the Harmony Hub sends out the IR signals to the device (behind the power switch).
MQTT: Activity_TV is starting -> Power Switch for TV is turned on (by separate MQTT message from your separate automation logic) -> IR Signals are sent to TV.