Create data types for components

[PavelHolec]

When components are used in hierarchical collections, it is often useful to have a data type to carry relevant information.

The future hierarchical Itinerary component will require such types anyway, so in order to be consistent, each component will get its data type.

This type will have matching signature as the init and will also be used for an extension init to be able to create the component out of it.

Open Questions

• Naming: BadgeData vs Badge.Data (not possible for components with generic content)