Discussion on how to implement Warning block

[lightningspirit]

https://github.com/editor-js/warning

This one is tricky as there's semantically no equivalent HTML tag for a "warning" message.

There are three options:

1. Assume that we won't tackle this one and let developers create their own renders
2. Use a mix of button and dialog tag (doesn't sound to me)
3. Create a simple render that can be extended by developers.