Improve blog post display

* Add a post date to each post
* Do not show the post date for tours
* Only show posts tagged "current-event" on the home page (hiding 37c3 entries)
* Use a custom template for sorting the summary list by title (instead of the default by date)

content/en/posts/2024-10-01-coming-up.md

@@ -1,6 +1,9 @@
 ---
 title: 'Get excited about the tours at 38c3!'
 date: 2024-10-31T09:00:00+01:00
+tags:
+  - current-event
+  - 38c3
 ---
 
 We are preparing tours again for 38c3. As soon as we have nailed down the details, we'll let you know here.