Redirect admin calls on subdomain to main
- prevent ambiguities on anything but the search views
- do not influence loading of resources
(from redmine: issue id 974, created on 2018-02-13tgradl, closed on 2018-02-13)
(from redmine: issue id 974, created on 2018-02-13tgradl, closed on 2018-02-13)