Matomo : stop setting cookies in doc pages

docs-fr/javascripts/matomo-tracking.js

 var _paq = window._paq || [];
 /* tracker methods like "setCustomDimension" should be called before "trackPageView" */
+_paq.push(['disableCookies']); // évite de mettre en place un bandeau RGPD
 _paq.push(['trackPageView']);
 _paq.push(['enableLinkTracking']);
 (function() {