Fix bug on articles changing section id over time

[RouxRC]

Solution is probably to store section_id of articles at step level instead of article level

• [ ] Titre IV Chapitre 3 at http://www.lafabriquedelaloi.fr/articles.html?loi=pjl10-027
• [ ] Grenelle II https://www.lafabriquedelaloi.fr/articles.html?loi=pjl08-155

Might be easier after doing https://github.com/regardscitoyens/the-law-factory-parser/issues/66

[boogheta]

Senate introduced subsections limits inside previous unique chapter : new articles get inside Chapitre 2 and 4 but others remain in chapter one