[Formulus] Improved app icon

[r0ssing]

Component

• formulus (React Native mobile app)
• formulus-formplayer (React web app)
• synkronus (Go backend server)
• synkronus-cli (Command-line utility)
• Documentation
• Other (please specify)

Feature Description

Let's have a nicer and more ODEish icon for Formulus 🦒
Perhaps one of these?