Add spam-training, spam-reviewing rights

Replaced the check for a moderator role in certain spam-training and
-reviewing points. Make sure modhelpers can check, too.

lib/profilenoticestream.php

@@ -95,7 +95,7 @@ class ProfileNoticeStream extends ScopingNoticeStream
 
         if (common_config('notice', 'hidespam')) {
             if ($this->streamProfile->hasRole(Profile_role::SILENCED) &&
-                (empty($this->userProfile) || !$this->userProfile->hasRole(Profile_role::MODERATOR))) {
+                (empty($this->userProfile) || !$this->userProfile->hasRight(Right::REVIEWSPAM))) {
                 return true;
             }
         }

lib/right.php

@@ -68,5 +68,7 @@ class Right
     const CREATEGROUP        = 'creategroup';
     const WEBLOGIN           = 'weblogin';
     const API                = 'api';
+    const REVIEWSPAM         = 'reviewspam';
+    const TRAINSPAM          = 'trainspam';
 }