feat(waybar): update battery module

* Remove `format-charging` and `format-plugged` settings in favor of just using the graduated battery level icons. Also  is a depreciated/removed Nerd Font icon. If we want to visually differentiate the charging state, CSS rules in `~/.config/waybar/style.css` might be a better way to handle that.
* Remove the commented lines because it is unlikely we will ever want these specific settings.
* Remove PBPbattery module and associated script. It is all commented out anyway. This feature has been built-in to Waybar for some time now; a custom script is no longer needed.

.config/waybar/style.css

@@ -73,8 +73,7 @@ Arc-Dark Color Scheme
 #pulseaudio,
 #temperature,
 #tray,
-#idle_inhibitor,
-#custom-PBPbattery {
+#idle_inhibitor {
     padding:0.5rem 0.6rem;
     margin: 1px 0px;
 }