Code of Conduct

## What
"Community guideline", "Contributing guidelines", "Rules", "Code of ethics", "`Literally why i got banned while playing WoW in a guild 8 years ago`" or "Code of Conduct", you name it! 👻

This issue is to discuss a potential code of conduct derived from [Ruby Community Conduct Guideline](https://www.ruby-lang.org/en/conduct/). This issue is NOT to discuss if we need to have a code of conduct. This will be discussed during 45th meeting: https://github.com/monero-project/meta/issues/1161

## Why
Just to structure things up a little and have some materials to act against bad actors. Some will say this is useless, but having extensively observed (and interacted with) both sides of the coin if it is done correctly it can only be beneficial to everyone.

## Where
New file in repo:
`/CODE_OF_CONDUCT.md`

## How
```
This document provides community guidelines for a respectful and collaborative place for anyone who is willing to contribute to Cuprate project. It applies to all “collaborative space”, which is defined as community communications channels (such as Github, Matrix, IRC, etc...).

- Everyone is welcome! As such, participants will be tolerant of opposing views.
- Participants language and actions should be free of insults and/or hostility.
- When interpreting the words and actions of others, participants should first assume good intentions.
- Behavior which can be reasonably considered hostile or repetitively offensive will not be tolerated.
- We are an international project, focused solely on improving our software. As such participants will refrain to discuss politics, unless directly concerning Cuprate.
- Participants should engage privately with owners or maintainers to resolve and/or mediate a situation. Even if hard at first glance, avoid pouring fuel on the fire.
```