Add Version Selector to v1.4 (#4746)

* Add Version Selector to v1.4

* upgrade to newer header

* change include_cached to include

* move head.html to correct location

* remove seo

* add footer-scripts.html

* turn on global nav

* fix docs nav link

_config.yml

@@ -19,6 +19,27 @@ defaults:
       version: "v1.4"
       githubbranch: "v1.4.12"
       docsbranch: "release-1.4"
+      versions:
+        - fullversion: "v1.7.3"
+          version: "v1.7"
+          githubbranch: "v1.7.3"
+          docsbranch: "release-1.7"
+          url: https://kubernetes.io/docs/home/
+        - fullversion: "v1.6.8"
+          version: "v1.6"
+          githubbranch: "v1.6.8"
+          docsbranch: "release-1.6"
+          url: https://v1-6.docs.kubernetes.io/docs/home/
+        - fullversion: "v1.5.7"
+          version: "v1.5"
+          githubbranch: "v1.5.7"
+          docsbranch: "release-1.5"
+          url: https://v1-5.docs.kubernetes.io/docs/
+        - fullversion: "v1.4.12"
+          version: "v1.4"
+          githubbranch: "v1.4.12"
+          docsbranch: "release-1.4"
+          url: https://v1-4.docs.kubernetes.io/docs/
   -
     scope:
       path: "docs"