Introduce a hook to auto dispose view models

[MidhunSureshR]

Introduces a hook that ties the lifecycle of the view-model to that of the calling react component.

We follow a bottom up approach in our MVVM refactors. As a consequence, we will have to create view-models in react components until we're done fully moving the code to our new architecture. This introduces the problem of how the view-models should be marked as disposed (i.e who actually calls vm.dispose()).

With this hook, you would:

const vm = useAutoDisposedViewModel(() => new FooViewModel(...));

Which would be the equivalent of

const vm = new FooViewModel(...);

[MidhunSureshR]

If we're okay with the view-model returned from this hook being undefined, we could just delay creating the vm to the effect body below. But we would have to always vm && <FooView vm={vm}> and vm?.doSomething().

It would also mean that all views would require an additional render (effect body always runs after render so the vm is only created after one render) before they are mounted. Also for view-models that immediately start doing async operations on instantiation, they would be delayed by one render cycle. But I doubt any of these would have actual performance implications.

I personally favor this approach because it feels equivalent to just calling the vm ctor.