use in-line sourcemaps for javascripts (#4453)

awx/ui/grunt-tasks/browserSync.js

@@ -12,7 +12,6 @@ module.exports = {
             ]
         },
         options: {
-            open: 'external',
             proxy: {
                 target: `https://${django_host}:${django_port}`,
                 ws: true

awx/ui/webpack.config.js

@@ -100,7 +100,7 @@ var dev = {
             'select2': path.resolve() + '/node_modules/select2/dist/js/select2.full.js'
         }
     },
-    devtool: 'sourcemap',
+    devtool: 'inline-source-map',
     watch: true,
 };