Add collapsing tray to waybar (#130)

Co-authored-by: David Heinemeier Hansson <david@hey.com>

config/waybar/style.css

@@ -17,6 +17,7 @@
 }
 
 #custom-dropbox,
+#tray,
 #cpu,
 #battery,
 #network,
@@ -28,6 +29,10 @@
   margin-right: 13px;
 }
 
+#custom-expand-icon {
+  margin-right: 12px;
+}
+
 tooltip {
   padding: 2px;
 }