docs: Block /internal/ on every published docs version

The internal module is deleted on main, but the release branches still
contain it and Antora publishes their content too. A forced netlify 404
covers all versions at the serving layer without backporting the
deletion.

Author: lfrancke

netlify.toml

@@ -7,6 +7,14 @@
   to = "https://hub.stackable.tech/crds"
   status = 301
 
+# The internal module is deleted on main but still exists on the release
+# branches; this blocks it for every published version without backports.
+[[redirects]]
+  from = "/home/:version/internal/*"
+  to = "/404.html"
+  status = 404
+  force = true
+
 [[redirects]]
   from = "/home/stable/release_notes.html"
   to = "/home/stable/release-notes"