CC-2607: Abilitiy to adjust stream bitrate, type, etc from the UI

interface

- dummy page "Stream Setting" page for the test
- StreamSetting model is added
- set owner and group as 'pypo' for liquidsoap.cfg
- pypofech handle 'update_stream_setting' command

airtime_mvc/application/configs/navigation.php

@@ -58,6 +58,12 @@ $pages = array(
                 'module'     => 'default',
                 'controller' => 'Preference',
                 'action'     => 'directory-config'
+            ),
+            array(
+                'label'      => 'Stream Setting',
+                'module'     => 'default',
+                'controller' => 'Preference',
+                'action'     => 'stream-setting'
             )
         )
     ),