Add mac info message on boot normal

[AlexValois]

When several devices are used and several are waiting their configuration, it is useful to check the mac address in Homie-ota server. Thanks to this change, the mac appear in inventory of the device in homie-ota server.

[marvinroger]

The DeviceId::get() is not actually the mac address, but something made up of the ESP8266 and flash chip IDs. So $mac is probably bad named.

[AlexValois]

Indeed, this is only the last half of the mac to which 0e is added. I will rename it.

thanks

[marvinroger]

I'll merge this, but thinking about it deviceId is kind of confusing, mac is probably better, even though it's not actually a MAC address.

[jpmens]

hwaddr (Hardware address) ?

[jamesmyatt]

There should be a real (station) MAC address available somewhere. In
Nodemcu, it's wifi.sta.getmac(): https://nodemcu.readthedocs.io/en/master/en/modules/wifi/#wifistagetmac.

[marvinroger]

I am considering replacing the hardware device ID (which is, as said above, something made up of the ESP8266 and flash chip IDs) by the complete 12 characters MAC address. Read esp8266/Arduino#2309 for the reason why, but TL; DR:

@igrr: There are now more OTP bytes used to set MAC address because we have run out of space with three bytes. getChipID doesn't take these new bytes into account, it has to be updated.
Edit: using MAC address as unique ID a good approach for now.