refactor: update content structure and layout templates

- Updated author format in content files
- Added section field to content files
- Simplified categories format
- Removed no-category.html layout
- Updated list.html and single.html layouts
- Updated index.html layout
- Updated generate-content.js script
- Do not index content with git

content/informatique/2019-06-ipv6-serveur-scaleway-dedibox/index.md

@@ -6,9 +6,10 @@ slug: "ipv6-serveur-scaleway-dedibox"
 wordpress_id: 439
 excerpt: "Online.net est un prestataire de services, qui fournit par exemple la location de serveurs dédiés. Online.net est une…\n"
 featured_image: ""
-author: {"id":1,"name":"Kevin"}
-categories: [{"id":14,"name":"Informatique","slug":"informatique"}]
+author: "Kevin"
+categories: ["Informatique"]
 tags: []
+section: "informatique"
 ---
 
 </p>