Ability to search by additional-domains

[BranchS]

• [x] I have searched open issues and pull requests. The issue I'm creating is not a duplicate of an existing open issue or pull request.

Information about the feature to be added:

It would be great if the https://2fa.directory/ site supported searching by additional domains. For example, Xfinity returns a result, but Comcast does not (even though Comcast.com is an additional-domain of Xfinity, as they are the same company)