Revert "Use official Hugo docker image instead of the outdated klakegg/hugo"

This partially reverts !673 (merged) since we are affected by a race condition which sometimes leads to an empty nested menu in the left panel. Once, this issue is fixed we can come back to the new hugo version.

themes/apertis/layouts/partials/footer.html

@@ -29,9 +29,9 @@
         
         
         <p>
-          {{ .Site.Params.name }}
+          {{ .Site.Author.name }}
           &nbsp;&bull;&nbsp;
-          {{ .Site.Lastmod.Format "2006" }}
+          {{ .Site.LastChange.Format "2006" }}
 
           {{ if .Site.Title }}
             &nbsp;&bull;&nbsp;