Extract date from URL for Le Monde

Summary:
Article URLs contain /YYYY/MM/DD/ relevant information.

Fixes T514.

Test Plan:

• Go to http://tools51.nasqueron.org/wikimedia/write/sourcetemplatesgenerator/
• Test http://www.lemonde.fr/pixels/article/2015/07/24/comment-le-deep-learning-revolutionne-l-intelligence-artificielle_4695929_4408996.html

Reviewers: dereckson

Subscribers: ledesillusionniste

Maniphest Tasks: T514

Differential Revision: http://devcentral.nasqueron.org/D30