Translations for French

1. New locale file
2. HTML/CSS changes where necessary

TODO:
* Check all links
* Check that all links keep you in the same lang
* Check that all the strings are covered
* Add links to FAQ [done]

Missing:
* menu.wiki_version
* privacy.summary
* privacy.total_requests
* privacy.information_was_produced
* privacy.bubble_graph_fineprint [done]
* privacy.show_all
* content.title [done]

Change-Id: I21100d04e5824c7dcdb2d21087313cf8ee451f94