Fix acceptance

* Fix acceptance info API to return user_id
* Adjust the url sent in the role / license acceptance email
  ```
  Change the url to <webview.url>/contents/<id>@draft/role-acceptance

  MANUAL-UPGRADE: Add "webview.url" to the ini file (e.g. development.ini)
  ```
Yes I've thought about that as well.  I think it's a good idea.