Create Onboarding screens

The new Onboarding Process is split into 2 parts: Onboarding and Authentication. The Onboarding is the first screen when the app is first launched. In Onboarding there should be 4 screens displayed with general info about the app. Use SwiftUI design patterns and features to do this.

Branch: onboardingScreens_swiftUi

• Create screens with information about the app
• Keyboard functionality
• Improve error handling (in AuthenticationViewModel)
• Login with Google
• Create test cases

Oli:

• Change Icons