[CALCITE-6843] Fix CSP policy for Lato font used by websites

Author: F21

site/_includes/top.html

@@ -5,6 +5,7 @@
   <title>{{ page.title }}</title>
   <meta name="viewport" content="width=device-width,initial-scale=1">
   <meta name="generator" content="Jekyll v{{ jekyll.version }}">
+  <meta http-equiv="Content-Security-Policy" content="style-src 'self' https://fonts.googleapis.com; font-src 'self' https://fonts.gstatic.com;">
   <link rel="stylesheet" href="//fonts.googleapis.com/css?family=Lato:300,300italic,400,400italic,700,700italic,900">
   <link rel="stylesheet" href="{{ site.baseurl }}/css/screen.css">
   <link rel="icon" type="image/x-icon" href="{{ site.baseurl }}/favicon.ico">