Follow-up from "Show the sensorML from the frontend"

The following discussion from !281 (merged) should be addressed:

• @tim.eder started a discussion: (+1 comment)

  SensorML export as blob works fine on the frontend. However the user experience is not optimal yet. The SensorML opens as a blob in a new tab. This is ok for simply viewing the data, but it makes it hard to download the file (on Chrome "Save as" is disabled).

  In a future release, we could implement a direkt download functionality. According to a quick google search, this requires a strange workaround with a hidden <a />-tag: https://stackoverflow.com/questions/19327749/javascript-blob-filename-without-link