[Nut-upsdev] New nutdrv_qx sub driver - protocol v15&16

[Nick Mayerhofer]

Hi,
I tested nutdrv_qx additions, introduced by @zykh, for a couple of
months now and changed only small things.

You can reach the repository via [1].
Please review the item_t array (starting at [2]) and give me feedback,
or change it directly.

Missing is the complete documentation, which I'm trying to get time for
since the last six months, but I don't.
Best, Nick

[1]
https://github.com/nickma82/nut/tree/nutdrv_qx_voltronic-sunny_rebased+command
[2]
https://github.com/nickma82/nut/blob/nutdrv_qx_voltronic-sunny_rebased%2Bcommand/drivers/nutdrv_qx_voltronic-sunny.c#L600