Quickstart and documentation widgets now use main site URL for API

[#52044647]

_layouts/default.html

@@ -1,7 +1,6 @@
 ---
 main_site_url: http://springframework.io
 forum_url: http://forum.springframework.io
-api_base_url: http://localhost:8080
 ---
 
 <!DOCTYPE html>
@@ -26,7 +25,7 @@ api_base_url: http://localhost:8080
   <script type="text/javascript" src="js/projectDocumentationWidget.js"></script>
   <script type="text/javascript" src="js/application.js"></script>
   <script type="text/javascript">
-    var apiBaseUrl = "{{ page.api_base_url }}";
+    var apiBaseUrl = "{{ page.main_site_url }}";
     var projectId = "{{ site.projectId }}";
   </script>
   <meta name="google-site-verification" content="7qGntFPD9lWAVCtUu5U77v4l68PsTHf6xpzgjQv2j2M" />