read production date and append to hardware version

[transistorgit]

this adds the battery production date to the hardware version string. maybe somebody can make use of it to distinguish multiply dalys

[mr-manuel]

I added two fields that could be populated, which are displayed in the GUI under "Device" page:

venus-os_dbus-serialbattery/etc/dbus-serialbattery/dbushelper.py

Lines 132 to 137 in f79ce83

	self._dbusservice.add_path(
	"/Serial", self.battery.unique_identifier, writeable=True
	)
	self._dbusservice.add_path(
	"/DeviceName", self.battery.production, writeable=True
	)

Could you use them instead of adding it to self.hardware_version?

[mr-manuel]

I made some changes, see 6c4c545