Add setup info regarding the CSP

data/siteMetadata.js

@@ -18,6 +18,8 @@ const siteMetadata = {
   linkedin: 'https://www.linkedin.com',
   locale: 'en-US',
   analytics: {
+    // If you want to use an analytics provider you have to add it to the
+    // content security policy in the `next.config.js` file.
     // supports plausible, simpleAnalytics, umami or googleAnalytics
     plausibleDataDomain: '', // e.g. tailwind-nextjs-starter-blog.vercel.app
     simpleAnalytics: false, // true or false
@@ -30,6 +32,8 @@ const siteMetadata = {
     provider: 'buttondown',
   },
   comment: {
+    // If you want to use a commenting system other than giscus you have to add it to the
+    // content security policy in the `next.config.js` file.
     // Select a provider and use the environment variables associated to it
     // https://vercel.com/docs/environment-variables
     provider: 'giscus', // supported providers: giscus, utterances, disqus