Turn interactive tutorials into custom 404 pages

Katacoda has shut down for good, and we have not added a local /
in-project alternative playground in the time since. Serving a 404 helps
cement that these pages are no longer part of the site.

content/en/docs/tutorials/kubernetes-basics/create-cluster/cluster-interactive-gone.html

@@ -1,5 +1,11 @@
 ---
-title: Interactive Tutorial - Creating a Cluster
+title: Not found
+# This page was previously titled "Interactive Tutorial - Creating a Cluster"
+# before Katacoda shut down.
+#
+# There is no need to localize this Not Found page; the website automatically
+# serves a 404 response when a page is missing. If you have an existing localized
+# version of this page, it is OK to remove that localized version.
 weight: 20
 headless: true
 toc_hide: true

content/en/docs/tutorials/kubernetes-basics/deploy-app/deploy-interactive-gone.html

@@ -1,5 +1,11 @@
 ---
-title: Interactive Tutorial - Deploying an App
+title: Not found
+# This page was previously titled "Interactive Tutorial - Deploying an App"
+# before Katacoda shut down.
+#
+# There is no need to localize this Not Found page; the website automatically
+# serves a 404 response when a page is missing. If you have an existing localized
+# version of this page, it is OK to remove that localized version.
 weight: 20
 headless: true
 toc_hide: true

content/en/docs/tutorials/kubernetes-basics/explore/explore-interactive-gone.html

@@ -1,5 +1,11 @@
 ---
-title: Interactive Tutorial - Exploring Your App
+title: Not found
+# This page was previously titled "Interactive Tutorial - Exploring Your App"
+# before Katacoda shut down.
+#
+# There is no need to localize this Not Found page; the website automatically
+# serves a 404 response when a page is missing. If you have an existing localized
+# version of this page, it is OK to remove that localized version.
 weight: 20
 headless: true
 toc_hide: true

content/en/docs/tutorials/kubernetes-basics/expose/expose-interactive-gone.html

@@ -1,5 +1,11 @@
 ---
-title: Interactive Tutorial - Exposing Your App
+title: Not found
+# This page was previously titled "Interactive Tutorial - Exposing Your App"
+# before Katacoda shut down.
+#
+# There is no need to localize this Not Found page; the website automatically
+# serves a 404 response when a page is missing. If you have an existing localized
+# version of this page, it is OK to remove that localized version.
 weight: 20
 headless: true
 toc_hide: true

content/en/docs/tutorials/kubernetes-basics/scale/scale-interactive-gone.html

@@ -1,5 +1,11 @@
 ---
-title: Interactive Tutorial - Scaling Your App
+title: Not found
+# This page was previously titled "Interactive Tutorial - Scaling Your App"
+# before Katacoda shut down.
+#
+# There is no need to localize this Not Found page; the website automatically
+# serves a 404 response when a page is missing. If you have an existing localized
+# version of this page, it is OK to remove that localized version.
 weight: 20
 headless: true
 toc_hide: true

content/en/docs/tutorials/kubernetes-basics/update/update-interactive-gone.html

@@ -1,5 +1,11 @@
 ---
-title: Interactive Tutorial - Updating Your App
+title: Not found
+# This page was previously titled "Interactive Tutorial - Updating Your App"
+# before Katacoda shut down.
+#
+# There is no need to localize this Not Found page; the website automatically
+# serves a 404 response when a page is missing. If you have an existing localized
+# version of this page, it is OK to remove that localized version.
 weight: 20
 headless: true
 toc_hide: true

static/_redirects

@@ -34,6 +34,14 @@
 /docs/reference/kubectl/cheatsheet/   /docs/reference/kubectl/quick-reference/ 301
 /kubectlguide /docs/reference/kubectl/quick-reference/ 302
 
+# Serve custom "not found" pages
+/docs/tutorials/kubernetes-basics/expose/expose-interactive/ /docs/tutorials/kubernetes-basics/expose/expose-interactive-gone/ 404
+/docs/tutorials/kubernetes-basics/scale/scale-interactive/ /docs/tutorials/kubernetes-basics/scale/scale-interactive-gone/ 404
+/docs/tutorials/kubernetes-basics/create-cluster/cluster-interactive/ /docs/tutorials/kubernetes-basics/create-cluster/cluster-interactive-gone/ 404
+/docs/tutorials/kubernetes-basics/explore/explore-interactive/ /docs/tutorials/kubernetes-basics/explore/explore-interactive-gone/ 404
+/docs/tutorials/kubernetes-basics/deploy-app/deploy-interactive/ /docs/tutorials/kubernetes-basics/deploy-app/deploy-interactive-gone/ 404
+/docs/tutorials/kubernetes-basics/update/update-interactive/ /docs/tutorials/kubernetes-basics/update/update-interactive-gone/ 404
+
 /docs/concepts/abstractions/controllers/garbage-collection/     /docs/concepts/workloads/controllers/garbage-collection/ 301
 /docs/concepts/abstractions/controllers/statefulsets/     /docs/concepts/workloads/controllers/statefulset/ 301
 /docs/concepts/abstractions/init-containers/     /docs/concepts/workloads/pods/init-containers/ 301