[WIP] Sane action ordering for sync effects

[grzegorz-bielski]

Addresses #21

@GrzegorzKazana I couldn't figure out how to make it work with an observeOn, so instead, I delegated the effects subscription.

It means that no effect will be run if there aren't any subscribers to the state$. This is clearly a breaking change, it might need more tests.

Available from npm at @rxsv/core@2.0.0-alpha.0

[GrzegorzKazana]

Dang, I thought it would be a simpler fix.
I think I got it working using the observeOn. Will try to open a PR with that today, so we can discuss what approach is better.

[GrzegorzKazana]

@grzegorz-bielski please have a look at #26, got it working with observeOn, seems like a cleaner solution to me

[grzegorz-bielski]

Having to rely on state$ subscription is too big of a drawback. Making every effect async seems like a better alternative.
The core issue is addressed in #26