Describe layout component from UIDL

[alexnm]

Currently we assume that the first node inside the root.content is describing the different routes/states of the application.

We may want to describe some sort of layout component around the main area where routes are deciding which content to show. For example, we could describe headers, footers, side navigations, etc.

Because each project flavor has specific ways of working with routes, this might be tricker to implement in one flow.

[vladnicula]

This is a tricky subject now that I think about it. We can always have components that support different props for various section of their layout, so we can already support layouts. Adding "hardcoded" supported for a specific way of using layouts is risky in my opinion.

Furthermore, the state management (via state machine) would benefit us more in terms of the flexibility we offer and might require a lot more work to properly implement if we do go ahead and support another type of structural support for the entire app, like these layout components.