interest-cohort support

[ghost]

Would be nice if this was included as a directive. Chromium browsers throw a warning in console about it. Although it's not really CSP but a Permissions-Policy header.

https://web.dev/articles/floc#do_websites_have_to_participate_and_share_information

interest-cohort=() to opt out of sharing data.

[ghost]

Actually this is easily added in nginx.