Add section for supported networks to the website

[johannesmoormann]

Overview

Currently we only mention the supported networks in a small and hardly visible section.

Goals

Prominently highlight the supported networks on the website

Requirements

• [ ] design specification
• [ ] logos
• [ ] Load supported networks from gateway

Screens

rough draft tbd with @liliiaorlenko

• Figma: https://www.figma.com/file/F6xayQPByTA0y6pFzfzuTE/Main-Page?node-id=1%3A77
• Zeplin:

Links

[rmeissner]

Should this be part of https://github.com/gnosis/safe-landing-page?

[liliiaorlenko]

Designs with logos: https://www.figma.com/file/F6xayQPByTA0y6pFzfzuTE/Main-Page?node-id=1%3A77