Add raw data field to manually parse data

[jogibear9988]

From @systemofapwne on December 16, 2018 21:59

Hi,
I already wrote an issue on your "wm-bus" library. There, I asked for "Techem HKV data II" support, which seems to use a proprietary format. I suggested to either incorporate that meter or to make the raw data-stream usable in ioBroker.
I forked your project and realized exactly the later one: Every datagram received is now pushed forward to "wm-bus.0.raw", which allows to externally parse the received data (which for me is the quickest solution right now).
Feel free to implement my changes to your project.

Cheers,
Klaus

Copied from original issue: soef/ioBroker.wm-bus#23