* validation
  * must: name
  * format: connection
* UI
  * don't show delete action if the milter is defined in base
    milter-manager.conf.
  * show missing fields
    * user name
    * timeouts
    * command options?
* control/status
* implement get-status of milter-manager-controller. YAML?
* config/reload
* config/security
  * privilege mode
* admin whitelist
