Add support for the Cross-Origin-Opener-Policy (COOP) header

Problem/Motivation

While running a Lighthouse report for a site, it mentioned adding support for the Cross-Origin-Opener-Policy (COOP) header. My first thought was that the Security Kit module already has support for that. It currently does not.

Proposed resolution

Add support for the COOP header https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Cros...