Add official Code of Conduct to Docs Website

[retiutut]

We have a GUI Code of Conduct: https://github.com/OpenBCI/OpenBCI_GUI/blob/master/CODE_OF_CONDUCT.md

But it would be best to have a public and prominent Code of Conduct that can be referenced in extreme cases that covers how OpenBCI interacts with users via our website, repositories, emails, socials, and overall online presence in official capacities.

We want to continue to grow our global Community in a sustainable way while also communicating what is and is not acceptable.

• Should be able to copy the code of conduct from the GUI but mention where it applies.
• Double check the language in this older document against an open-standards Code of Conduct from a reputable source.

[retiutut]

Would go under FAQ/Policies

[retiutut]

@isaacplotkin Any progress on this? I think we just need feedback from a few other OpenBCI team members to greenlight a Code that you've found.