feat(mail): Deletion of mail older than x. Closes #6023. Remove also template folder. Change SOGoDisableMailCleaning to SOGoEnableMailCleaning (disabled by default).

SoObjects/SOGo/SOGoSystemDefaults.m

@@ -933,9 +933,9 @@ NSComparisonResult languageSort(id el1, id el2, void *context)
   return [self stringForKey: @"SOGoURLCreateAccount"];
 }
 
-- (BOOL) disableMailCleaning
+- (BOOL) enableMailCleaning
 {
-  return [self boolForKey: @"SOGoDisableMailCleaning"];
+  return [self boolForKey: @"SOGoEnableMailCleaning"];
 }
 
 @end