Improve visibility of Getting Started on the landing page

[n-boshnakov]

What would you like to be added:
We should add the Getting Started section to the main navbar of the landing page for better visibility.

Why is this needed:
Getting Started should be easy to locate and access.

[Kostov6]

Getting started is the first section under documentation. Kubernetes website follows the same approach https://kubernetes.io/docs/home/

Also it is literally under docs when clicking Documentation for all personas