This pull request allows dynamic oAuth redirects by adding an origins option to the oAuth configuration. This can be added instead of the redirect option to include a list of URLs that are allowed to make oAuth requests. It will use the Referer HTTP header from the original request to redirect back to. For example a configuration like

{
  "authentication": {
    "oauth": {
      "origins": [
        "https://feathersjs.com",
        "https://feathers.cloud"
      ]
    }
  }
}

Would allow and redirect any request made from those domains.

• Closes OAuth2 dynamic redirect doesn't work #2285
• Closes Allow multiple oAuth redirect domains #2430