Set Power on level brightness according to last brightness state from HA

[AdamN1]

DALI bus support setting brightness level of the lamp after power on we can use this to store last brightness state received from HA. Situation:

1. change brightness level in HA
2. dali2mqtt send new new brightness level to lamp
3. dali2mqtt store active brightness level in the lamp

In my configuration with conventional switch it will be great to support this because after power reset lamp will be using last state.

[dgomes]

writing constantly to the ballast flash is not a good ideia (the flash will wear off)

We can create command topic for that, but I would advise against using it often