Update nixpkgs -> update hugo to 0.152.2

That also requires a couple of changes in the template. For some of them I just remove the corresponding feature like analytics and comments.

content/donating-challenge/_index.md

@@ -3,10 +3,10 @@ menu: main
 title: Donating challenge
 weight: 4
 outputs: [ "HTML" ]
-_build:
+build:
   render: true
 cascade:
-  _build:
+  build:
     render: false
     list: true
 ---