Added the ability to enable borders for the bar. (#428)

* Added the ability to configure a border for the bar.

* Added the right color for configs

themes/everforest_vivid.json

@@ -341,5 +341,6 @@
   "theme.bar.menus.menu.network.switch.puck": "#454b53",
   "theme.bar.menus.menu.network.switch.disabled": "#2f383e",
   "theme.bar.menus.menu.network.switch.enabled": "#e69875",
-  "theme.bar.buttons.systray.customIcon": "#d8caac"
+  "theme.bar.buttons.systray.customIcon": "#d8caac",
+  "theme.bar.border.color": "#83c092"
 }