[FLINK-20832] Deliver bootstrap css and js ourselves

Author: wuchong

_layouts/base.html

@@ -10,7 +10,7 @@
     <link rel="icon" href="{{ site.baseurl }}/favicon.ico" type="image/x-icon">
 
     <!-- Bootstrap -->
-    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
+    <link rel="stylesheet" href="{{ site.baseurl }}/css/bootstrap.min.css">
     <link rel="stylesheet" href="{{ site.baseurl }}/css/flink.css">
     <link rel="stylesheet" href="{{ site.baseurl }}/css/syntax.css">
 
@@ -59,8 +59,8 @@
     </div><!-- /.container -->
 
     <!-- Include all compiled plugins (below), or include individual files as needed -->
-    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>
-    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery.matchHeight/0.7.0/jquery.matchHeight-min.js"></script>
+    <script src="{{ site.baseurl }}/js/jquery.matchHeight-min.js"></script>
+    <script src="{{ site.baseurl }}/js/bootstrap.min.js"></script>
     <script src="{{ site.baseurl }}/js/codetabs.js"></script>
     <script src="{{ site.baseurl }}/js/stickysidebar.js"></script>