feat: new Web UI build system

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

static/app/core/providers.resource.js

@@ -1,10 +0,0 @@
-(function () {
-  'use strict';
-
-  angular
-    .module('traefik.core.provider', ['ngResource'])
-    .factory('Providers', ['$resource', function ($resource) {
-      return $resource('/api/providers');
-   }]);
-
-})();