Remove Gutenberg's global styles

[vinkla]

This was recently introduced in Gutenberg and is yet another thing forced on theme developers without any documentation or guides on how to disable it. This might have side effects. Only time will tell 🤷

---

In the pull request @mkkeck has written a comment which resonates a lot with my frustration which has led to the creation of this plugin in the first place.

General, I like the Gutenberg Editor, but sometimes there's project philosophy, which is not acceptable:

• Putting tons of new features, are knitted with hot needle, which breaking current themes and plugins
• New features rolled out to WordPress core, flagged as experimental, no opt-in or opt-out with no documentation
• Eat or die mentality of some peoples here