Switch to transifex for translations

All strings, urls and anchors are now in a single yml files for each language
Translation are generated into html by a translation jekyll tag plugin
Each html file and language remain independant
Outdated translations are not affecting other translations
Specific content can be added independently on each .html file of each language
Urls and anchors are translated once and dynamically applied everywhere

This change can allow to handle translations in a more efficient way. Allowing more translators to work without learning technicals behind github, html and such. Making translations updates more obvious and easy to handle. And it allows to have more reviews and teams in charge of each translation.