Refactor welcome wizard naming to more common wizard

[MAILPOET-1732]

assets/js/src/webpack_admin_index.jsx

@@ -16,4 +16,4 @@ import 'poll.jsx'; // side effect - assigns to MailPoet.Poll
 import 'settings/reinstall_from_scratch.js'; // side effect - adds event handler to document
 import 'subscribers/importExport/import.jsx'; // side effect - executes on doc ready, adds events
 import 'subscribers/importExport/export.js'; // side effect - executes on doc ready
-import 'welcome_wizard/wizard.jsx'; // side effect - renders ReactDOM to document
+import 'wizard/wizard.jsx'; // side effect - renders ReactDOM to document

assets/js/src/wizard/wizard.jsx

@@ -1,9 +1,9 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
 import { Route, HashRouter, Redirect } from 'react-router-dom';
-import WelcomeWizardStepsController from './steps_controller.jsx';
+import WelcomeWizardStepsController from './welcome_wizard_controller.jsx';
 
-const container = document.getElementById('welcome_wizard_container');
+const container = document.getElementById('mailpoet_wizard_container');
 
 if (container) {
   ReactDOM.render((

views/welcome_wizard.html

@@ -15,7 +15,7 @@
   var admin_email = <%= json_encode(admin_email) %>;
 </script>
 
-<div id="welcome_wizard_container"></div>
+<div id="mailpoet_wizard_container"></div>
 
 <div class="welcome_wizard_video">
     <iframe width="1" height="1" src="https://player.vimeo.com/video/279123953" frameborder="0"></iframe>