Feature request: Support additional-domains optional field

[rasa]

https://github.com/2factorauth/twofactorauth/blob/master/CONTRIBUTING.md#other-properties shows:

{
  "Site Name": {
    "domain": "site.com",
    "additional-domains": [
      "site.net",
      "site.io"
    ],
}

Can support for additional-domains be added?