[Crawler] Wikimedia Commons integration

[pasqLisena]

Wikimedia Commons is a great source of pictures, often together with the year.
Examples: Frans Timmermans, Brigitte Bardot.

In addition to Google Images, the crawler may benefit also of those pictures (fair use, less noisy).

Subtasks:

• Understand the difference between pages and categories
• Study the api (hard documentation)
• Integrate the results

[rtroncy]

In case we still want to implement this feature, https://commons.wikimedia.org/wiki/Commons:Structured_data/Media_search should be useful. Apparently, new features will be pushed later this month (advertized on the Wikidata mailing list)