Add support for referrers

[GrayHatter]

This breaks many sites that believe they can depend on this header for security.

[robinlinden]

See: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referer

[robinlinden]

@GrayHatter Can you add a link to a site that requires this, so whoever works on this can test it?

[GrayHatter]

A lot of US banks sites CDN, resources won't load without referrers.

Will verify and give a testcase next time I hate myself enough, or start on this.