Add in-page tabbing

[internetisaiah]

Feature description

Add in-page tabbing so you can have steps for windows and mac on the same page without taking up too much screen space or needing to add two separate articles to the left-side nav bar.

Ways to implement (optional)

• AsciiDoc Tabs extention

Examples (optional)

• Microsoft Azure Docs

[internetisaiah]

Currently being worked on. Trello card here: https://trello.com/c/BhoFD3Xy/168-design-in-page-tab-styles