Redesign landing page

Created by: cmeessen

Adjust landing page to be shown in Helmholtz corporate design.

The page should be completely reworked and contain placeholders for the following content

• What is the Research Software Directory and what is it for?
• Short teaser for the latest Software Spotlight
• How to participate
• Participating Centres
• Partner Organisations

Other mandatory content

• Link to imprint
• Link to data protection declaration