Implement error-handling system

[erikbasargin]

Describe the solution you'd like

The error-handling system (for example, BannerManager) suppose to follow next points:

• Single instance in the app.
  It doesn't mean this is a singleton, with AppScript we can avoid it, for example AuthManager in Implementing User Authentication with Sign in with StackExchange #58
• Easy way/syntax to add some handling to some view. For example:

  SomeView {
      // ...
  }.alert(isPresented: ...) { ... }

• Managing errors by the special protocol to avoid some errors which we will not want to show 🙃