Respect the DNT / GPC headers

[johnbillion]

I couldn't immediately see if the dnt HTTP request header is respected by Altis Analytics. If not, it would be great if it was.

[roborourke]

There was an issue for that upstream on the plugin repo https://github.com/humanmade/aws-analytics/issues/14

Ultimately the header isn't supported across the board so we opted for working on the Consent API approach instead. It could be done still but no other Analytics provider except maybe Fathom make use of it. That said it's a minor change in terms of code so could still be done in future.

[johnbillion]

The browser landscape might have changed a bit since that issue. On the client side, Chrome, Firefox, Brave, and Edge all expose DNT as a setting now. On the server side I've no idea how widely supported the header is, it's entirely down to each individual web application to respect it.

[johnbillion]

There's also a new GPC header which I hadn't heard about before. Some links:

• https://www.theverge.com/2021/1/28/22252935/global-privacy-control-personal-data-tracking-ccpa-cpra-gdpr-duckduckgo
• https://globalprivacycontrol.org/press-release/20201007.html
• https://globalprivacycontrol.org/press-release/20210128