nav: move mapgl out of mapbox

src/config/navLinks.js

@@ -16,11 +16,13 @@
         {
           name: "Mapbox Test",
           url: "/mapbox/test"
-        },
-        {
-          name: "Map GL",
-          url: "/map-gl"
-        },
+        }
+      ]
+    },
+    {
+      name: "Map GL",
+      url: "/map-gl",
+      sublinks: [
         {
           name: "Map GL Test",
           url: "/map-gl/test"