ActionSheetState and AlertState for UIKit

[larryonoff]

Composable Architecture needs more UIKit support. So I suggest extending ActionSheetState and AlertState to support UIAlertController, i.e.

1. Remove ActionSheetState operation systems limitations.
2. Move ActionSheetState and AlertState into Common folder.
3. Add convenient initialisers to UIAlertController, e.g.

extension UIAlertController {

public static func actionSheet<Action>(
  state: ActionSheetState<Action>,
  send: @escaping (Action) -> Void
) -> UIAlertController

public static func actionSheet<Action>(
  store: Store<ActionSheetState<Action>, Action>,
  dismiss: Action
) -> UIAlertController

public static func alert<Action>(
  state: AlertState<Action>,
  send: @escaping (Action) -> Void
) -> UIAlertController

public static func alert<Action>(
  store: Store<AlertState<Action>, Action>,
  dismiss: Action
) -> UIAlertController

}

Looking forward to any comments.

PS. The same I would suggest to ReactiveSwift Composable.

[andreyz]

👋 your suggestion pushed me to finally make a PR with the UIKit helpers I've been using in production here #563. See if that fits your requirements.

[larryonoff]

Looks what I need :)