[Infopanel] add summary-descriptions for Infopanel and QuickMenu

Example for skinners in the "skin_display.xml" for this two screens:

<!-- QuickMenu -->
	<screen name="QuickMenu_summary" position="0,0" size="256,64">
		<widget source="parent.Title" render="Label" position="120,0" size="136,40" font="FdLcD;17" halign="center" valgin="bottom" />
		<widget source="parent.summary_description" render="Label" position="0,42" size="256,22" zPosition="1" font="FdLcD;20" halign="center" valign="center" />
	</screen>

<!-- Infopanel -->
	<screen name="Infopanel_summary" position="0,0" size="256,64">
		<widget source="parent.Title" render="Label" position="120,0" size="136,40" font="FdLcD;17" halign="center" valgin="bottom" />
		<widget source="parent.summary_description" render="Label" position="0,42" size="256,22" zPosition="1" font="FdLcD;20" halign="center" valign="center" />
	</screen>