feat: add data binding lists support

[mfazekas]

Summary

Adds ViewModelListProperty for dynamic list management at runtime, for now no hook just low level methods

API

• length - get list size
• instanceAt(index) - get ViewModelInstance at index
• append(instance) - add to end of list
• insert(instance, index) - insert at position
• remove(instance) - remove by reference
• removeAt(index) - remove at index
• swap(index1, index2) - swap items
• addListener(callback) - observe changes

Example

const listProperty = instance.listProperty('items');

// Add new item
const newItem = viewModel.createInstance();
listProperty.append(newItem);

// Remove item
listProperty.removeAt(0);

// Swap items
listProperty.swap(0, 1);

Test plan

• Added example page with list.riv test file
• iOS implementation
• Android implementation

Closes #11

[HayesGordon]

Two things to consider:

• We don't HAVE to name these similar to android/ios. We can use the naming convention that matches what is expected when working with lists in RN.
• We could add additional methods/overloads if those are commonly used in RN. For example in Dart I added firstOrNull instead of throwing, and overloads for operator [] and operator[]=. Maybe something like this possible here to

  @override
  ViewModelInstance operator [](int index) => instanceAt(index);

  @override
  void operator []=(
    int index,
    covariant FFIRiveViewModelInstanceRuntime value,
  ) =>
      insert(index, value);

[HayesGordon]

Good catch!

[HayesGordon]

Oh! This is what we did from the start. Nice abstration then!

[HayesGordon]

LGTM! Just need to decide if these methods names will be most familiar for RN

[HayesGordon]

Oh and all of the abstraction and Nitro is really paying off here 🙌 . This is really minimal code for a large feature.