Update code of conduct docs on the website to match current online platforms

[thibaudcolas]

Follow-up to Retire django-developers and django-users mailing list #1727 – with django-users and django-developers and IRC getting retired (see forum thread, there is code of conduct content that should be updated to stop mentioning them. First pass: djangoproject.com:#1808

I could see this being done either by changing the references to a more generic "online spaces" term, or to match the current online spaces. Either way I thought this would warrant an issue here, as the decision and wording would ideally be decided by the Code of Conduct WG.

Here are a few I spotted:

• CoC FAQ
• CoC enforcement
• CoC index page

[thibaudcolas]

Closed by #1808. On further reflection I think the changes there are spot on, and we can continue with the CoC WG over email.