Styling using only utility classes (like Tailwind)

It would be nice to have a global option supported by all (official) blocks that allows the following:

1. Do not add the default CSS for that block
2. Allow to add arbitrary class names to each element generated by a block

The custom class names (used for styling, like `text-lg`, `text-center`, `bg-gray-100`, etc.) can be added to the config when you initialize the editor with the various blocks.

This would work very well with Tailwind CSS and utility classes in general.

Currently it's painful to control the exact appearance of the elements generated by Editor.js.