New: Cleanup UI tooling, Update to Webpack 4, Gulp 4 (#655)

* New: Webpack 4

* New: Gulp 4

* New: Transpile UI for old browsers

Co-Authored-By: Mark McDowall <markus101@users.noreply.github.com>

frontend/src/Store/Actions/oAuthActions.js

@@ -1,6 +1,7 @@
 import $ from 'jquery';
 import { createAction } from 'redux-actions';
 import { batchActions } from 'redux-batched-actions';
+import createAjaxRequest from 'Utilities/createAjaxRequest';
 import requestAction from 'Utilities/requestAction';
 import getSectionState from 'Utilities/State/getSectionState';
 import updateSectionState from 'Utilities/State/updateSectionState';
@@ -88,7 +89,7 @@ function showOAuthWindow(url, payload) {
 }
 
 function executeIntermediateRequest(payload, ajaxOptions) {
-  return $.ajax(ajaxOptions).then((data) => {
+  return createAjaxRequest(ajaxOptions).then((data) => {
     return requestAction({
       action: 'continueOAuth',
       queryParams: {
@@ -97,7 +98,7 @@ function executeIntermediateRequest(payload, ajaxOptions) {
       },
       ...payload
     });
-  });
+  }).request;
 }
 
 //