[Documentation]: Add content to home page

[IbenTesara]

The current documentation site has a homepage which lacks content. On this page we want to give a mission statement and a general overview of what we want to do with the packages.

This text will be provided by team marketing, design should be made in cooperation with team design.

[WouterBas]

@IbenTesara, how's the progress on the design? Is there anything available yet?