feat: new Web UI build system

- use generator-gulp-angular by @swiip
- remove old static file

webui/src/app/index.config.js

@@ -0,0 +1,15 @@
+(function() {
+  'use strict';
+
+  angular
+    .module('traefik')
+    .config(config);
+
+  /** @ngInject */
+  function config($logProvider) {
+    // Enable log
+    $logProvider.debugEnabled(true);
+
+  }
+
+})();