Nigeria (Senate): Make Wikidata the primary source

[chrismytton]

As things currently are, if the official site hasn't been updated, which it often hasn't, then we have to add workarounds either in the scraper or in manual files in the everypolitician-data repo to correct that data.

If the data instead came from Wikidata then we could simply update things in Wikidata instead of having to do it at the scraper level. This would allow us the non-technical folks that run sites like http://www.shineyoureye.org/ to update any problems they find in the data themselves, rather than having to get someone technical to fix things at the code level.