Create CODE_OF_CONDUCT.md

[erlend-sh]

Defaulting to the Contributor Covenant for now.

Defaulting to Hyper’s minimalistic CoC for now.

[avdb13]

created by Coraline Ada Ehmke
opal/opal#941

Not very excited about a CoC coming from a person stalking others across several social media. I feel like this will do more harm than good as its rules are too vague and formal.
Something like Hyper's feels way more inviting and reasonable as

1. It's more personal as it's written by the project lead himself.
2. It reads way easier than the above.
3. We should focus on making the project more welcoming to new contributors, this does not happen by policing their behavior and language (people make mistakes).

Sure, we need some sort of guidelines at some point, but I'd rather keep a CoC out of the project for now as I want to believe that 90% people will adhere to these rules by default.

[erlend-sh]

Something like Hyper's feels way more inviting and reasonable

Oh, yeah that’s a beautifully simple one. Let’s start with that!

Not very excited about a CoC coming from a person stalking others across several social media.

That post is from 2015. I trust you’ll agree you were also a pretty different person way back in 2015? 😁