List: First-Party isolation CDNs

[jtagcat]

Is your feature request related to a problem? Please describe.
Many sites have one domain along the lines of sitename-cdn.com, sitenamestatic.com sitename-assets.com. Often for either blob storage or isolating (user) content.

They quite likely need them to work.

Describe the solution you'd like
Attempt to whitelist those domains as 1st party domains. In a separate repository.

Describe alternatives you've considered
Doing it all myself and repeating the work that is already done.