Kubernetes 1.8 reference docs (#5632)

* Kubernetes 1.8 reference docs

* Kubectl reference docs for 1.8

* Update side bar with 1.8 kubectl and api ref docs links

docs/api-reference/v1.8/node_modules/highlight.js/lib/languages/dockerfile.js

@@ -0,0 +1,21 @@
+module.exports = function(hljs) {
+  return {
+    aliases: ['docker'],
+    case_insensitive: true,
+    keywords: 'from maintainer expose env arg user onbuild stopsignal',
+    contains: [
+      hljs.HASH_COMMENT_MODE,
+      hljs.APOS_STRING_MODE,
+      hljs.QUOTE_STRING_MODE,
+      hljs.NUMBER_MODE,
+      {
+        beginKeywords: 'run cmd entrypoint volume add copy workdir label healthcheck shell',
+        starts: {
+          end: /[^\\]\n/,
+          subLanguage: 'bash'
+        }
+      }
+    ],
+    illegal: '</'
+  }
+};