Move to MAG Citations are primary source

[rhosking]

Currently Open Citations is the primary source used, but but both coverage and regular updates are lacking. The information for MAG is already available, so will replace Open Citations

[cameronneylon]

As we do this is it possible to incorporate back some of the timebased citation information such as:

• Citations in first year after publication
• Citations in first two years after publication
• etc.

Trying to figure out how to have sensible comparison information for the White Paper documents and I think we need something like this to show trends and changes over time. Not sure if this is a separate issue or whether it can be incorporated easily.

[rhosking]

added in linked pull request. Time-based citation information branched into separate issue #129