Provide screen component instead of rendering outside of expo

[floriangosse]

Right now the SDK renders outside the expo stack (I've tested it only on iOS). This can cause several problems as it lays over the expo screens and makes it impossible to open a screen in my app based on a custom action from my paywall.

If we have a SuperwallPaywall component that we can render as a parametrized route and gets opened by a similar functionality than registerPlacement we can utilize the expo stack.

To make it possible we would have to render the paywall on the native layer but provide it as a component that accepts parameters.

[linear]

SW-4408

[Makisuo]

Keeping the issue open for now, but won't be implementing this for the near future. We are planning to move more logic into TS next year, which will also include rendering.

[floriangosse]

@Makisuo maybe the implementation of RevenueCat can be an inspiration. They solved it quite well. Right now it's a really bad user experience when you have to open an additional app screen from within the paywall (via custom action). So some workaround of quick solution would already help quite a bit.