skel: xfce4-panel: replace xfce4-power-manager notification icon with battery panel plugin

- notification icon is deprecated/shows a broken icon
> https://gitlab.xfce.org/xfce/xfce4-power-manager/-/issues/104
> As a general note: if you're using the xfce4-panel don't use the trayicon. It's really the legacy option I left in to potentially enable users of other or mixed desktop environment setups to use xfce4-power-manager.

config/includes.chroot/etc/skel/.config/xfce4/panel/battery-1.rc

@@ -0,0 +1,18 @@
+display_label=false
+display_icon=true
+display_power=false
+display_percentage=false
+display_bar=false
+display_bar_time=false
+tooltip_display_percentage=true
+tooltip_display_time=true
+low_percentage=10
+critical_percentage=5
+action_on_low=1
+hide_when_full=0
+colorA=rgb(153,193,241)
+colorH=rgb(0,255,0)
+colorL=rgb(255,255,0)
+colorC=rgb(255,0,0)
+command_on_low=
+command_on_critical=