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/crypto/2022-12-comment-realiser-investissement/index.md

@@ -6,9 +6,10 @@ slug: "comment-realiser-investissement"
 wordpress_id: 5316
 excerpt: "Au même titre que l’immobilier locatif, le marché boursier ou trading est l’un des meilleurs placements financiers. Il…\n"
 featured_image: "https://www.mistergeek.net/wp-content/uploads/2022/12/bien-investir.jpg"
-author: {"id":1,"name":"Kevin"}
-categories: [{"id":332,"name":"Crypto","slug":"crypto"}]
+author: "Kevin"
+categories: ["Crypto"]
 tags: []
+section: "crypto"
 ---
 
 </p>