Use either tabbed layout or drop-down for main doc sections

### Is this a docs issue?

- [x] My issue is about the documentation content or website

### Type of issue

Other

### Description

There are tabs for Getting Started, Guides, Manuals, and Reference. A drop down also exists for this. 

### Location

https://docs.docker.com/get-started/docker-overview/

### Suggestion

I would choose one or the other. Tabs personally.