Moving the Cookie Store API to the WHATWG

[annevk]

@DCtheTall and I would like to propose moving https://github.com/WICG/cookie-store into the WHATWG. We'd like some advice from the SG with respect to whether a new Workstream is required.

As it happens it already has an almost suitable logo, just need to change the color: https://wicg.github.io/cookie-store/logo-cookies.svg.

[annevk]

Concrete proposal:

• Move this into the Fetch Workstream.
• Keep it as a standalone document.
• Eventually change the bits of the document where it calls into the IETF Cookies document to call into Fetch instead so we can more properly define the event story.