Remove dependency to downloadjs

[steff-o]

Is your feature request related to a problem? Please describe. Not really, but there are three different functions that performs client side file download: the downloadjs npm package, the origo utility function dowloadBlob (in download.js) and internally in exporttofile.js

Describe the solution you'd like All client side file downloads should use the origo utility function downloadBlob.

Describe alternatives you've considered Let it slide.

Additional context I am fully aware of the fact that I am the person who added the last implementation of the same functionality without realising that there already were two utility functions in the project that did exactly the same thing. Shame on me.