Add SwiftUI support

[KyNorthstar]

A new rethinking of the API will be needed. Input and suggestions are welcome!

[castdrian]

I think extending SwiftUI components to allow using the toasts would be decent, ie. buttons and pickers, toggles, that kinda stuff can be extended to behavior of something along the lines of this, where the specified action, such as clicking the button, toggling the toggle, selecting a picker item, easily triggers a confirmation notification

Button("hello") {
     print("pog")
}.bezelToast(message: "wow", icon: .pogIcon)

[KyNorthstar]

I like that idea, @castdrian! Any thoughts on how it would know when to show the toast?