[Metadata] GEOFON part of issue 166

[javiquinte]

This is the GEOFON part from issue #166 .

This station has similar issue. The are several Station elements. One of them is open, as are the channels in there, but there are other Station elements which have closed epochs. It is again maybe not wrong, but it is dangerous, as one needs to go through all the Station element to find out if one is still open. Having one Station element sounds like a safe solution.
http://geofon.gfz-potsdam.de/fdsnws/station/1/query/?net=HU&station=BEHE&channel=???&level=response

The channels are named BH* here, but the sensor looks like a short-period with a corner period below 10 s
https://geofon.gfz-potsdam.de/fdsnws/station/1/query/?net=SJ&station=SVIS&channel=???&level=response

Here there are only SP epochs included, but there is a BB sensor installed too (and hence the station is not listed in the _ADARRAY)
http://geofon.gfz-potsdam.de/fdsnws/station/1/query/?net=SK&station=LANS&channel=???&level=response