Refactor tabs implementation (#3268)

* Refactor tabs implementation

* tidy head.html

* test jquery-ui tabs

* Initial tabs code refactor

* test liquid parsing

* test liquid stack

* move into tabs.html

* test jekyll tabs

* construct array

* test cleaner way

* add example content

* test split hack

* fix md

* add site.emptyArray

* set good defaults

* fix CSS

* cleanup li

* fix a href

* fix content tabs

* add space to default

* remove a href underline

* rename docs/tab-test.md to docs/tab-example.md

* fix skip toc check

* add assignees

* add comment to reference example

* add documentation to example

* escape md

* move demo to top, pretty it up

* add word

* tweak wording

skip_toc_check.txt

@@ -43,6 +43,7 @@ docs/home/security.md
 docs/reference/deprecation-policy.md
 docs/search.md
 docs/sitemap.md
+docs/tabs-example.md
 docs/user-guide/accessing-the-cluster.md
 docs/user-guide/annotations.md
 docs/user-guide/application-troubleshooting.md