Added year to blog navigation (#402)

Modified the blog navigation to be `/blog/<YEAR>/<TITLE>` to help
preventing duplicated names.

Added a `404` page.

## Summary

- **New Features**
- Introduced a user-friendly "Not Found" error page with a clear message
and visual elements.
  
- **Improvements**
- Updated blog post permalink structure to include the publication year,
enhancing organization and SEO.

src/404.md

@@ -0,0 +1,12 @@
+---
+layout: "layouts/info.html"
+title: Oops! Not Found
+permalink: 404.html
+---
+
+If you were looking for something here, it may <span class="font-bold">have been moved</span>.
+
+You should go back to the <a href="/" class="link link-secondary">home page</a> and look from there.
+
+<img src="{{ '/img/not_found.webp' | url }}" class="h-80 mx-auto rounded-3xl border-accent border-2">
+

src/blog/blog.json

@@ -1,4 +1,4 @@
 {
     "layout": "layouts/blog.html",
-    "permalink": "/blog/{{ page.fileSlug }}.html"
+    "permalink": "/blog/{{ page.date.getFullYear() }}/{{ page.fileSlug }}.html"
 }