Explore adding Kotlin modules

[uber]

Explore adding Kotlin modules

[ZacSweers]

Some early thoughts on this: Would be nice if we could massage the API via extension methods into something like this:

myObservable
    .autoDispose()
    .scopeTo(provider)
    .around(...)

Would require some sort of annotation or lint to make sure people finish it. We could (I'm pretty sure) skip the intermediary type resolution since Kotlin is smarter with generics. Gets finicky with semantics though. Does it subscribe automatically then? How do you capture the forward return type?

Alternatively, we could keep the current subscribe entry point where it just returns something for use in Subscribe, but clean up the type resolution.