Refactor e2e's ApiService (#7101)

* Refactor e2e's ApiService

* Fix bits here and there

* [ci:force] Remove unused imports

* [ci:force] Extract shared part from adf-testing

* [ci:force] Extract StringUtils as well

* Make protractor's Logger not have duplicated code

* [ci:force]

e2e/content-services/directives/download-directive.e2e.ts

@@ -17,8 +17,7 @@
 
 import { ContentServicesPage } from '../../core/pages/content-services.page';
 import { FileModel } from '../../models/ACS/file.model';
-import {
-    ApiService,
+import { createApiService,
     BrowserVisibility,
     FileBrowserUtil,
     LoginPage,
@@ -64,7 +63,7 @@ describe('Version component actions', () => {
         location: browser.params.resources.Files.ADF_DOCUMENTS.TEXT_FOLDER.folder_location
     });
 
-    const apiService = new ApiService();
+    const apiService = createApiService();
     const uploadActions = new UploadActions(apiService);
     const usersActions = new UsersActions(apiService);