example configs: remove obsolete CSP configuration

installation/caddyfile-pleroma.example

@@ -22,27 +22,10 @@ example.tld  {
   }
 
   header / {
-    X-XSS-Protection "1; mode=block"
-    X-Frame-Options "DENY"
-    X-Content-Type-Options "nosniff"
-    Referrer-Policy "same-origin"
     Strict-Transport-Security "max-age=31536000; includeSubDomains;"
     Expect-CT "enforce, max-age=2592000"
-    Content-Security-Policy "default-src 'none'; base-uri 'self'; form-action 'self'; frame-ancestors 'none'; img-src 'self' data: https:; media-src 'self' https:; style-src 'self' 'unsafe-inline'; font-src 'self'; script-src 'self'; connect-src 'self' wss://{host}; upgrade-insecure-requests;"
   }
 
-  # If you do not want remote frontends to be able to access your Pleroma backend server, remove these lines.
-  # If you want to allow all origins access, remove the origin lines.
-  # To use this directive, you need the http.cors plugin for Caddy.
-  cors / {
-    origin https://halcyon.example.tld
-    origin https://pinafore.example.tld
-    methods POST,PUT,DELETE,GET,PATCH,OPTIONS
-    allowed_headers Authorization,Content-Type,Idempotency-Key
-    exposed_headers Link,X-RateLimit-Reset,X-RateLimit-Limit,X-RateLimit-Remaining,X-Request-Id
-  }
-  # Stop removing lines here.
-
   # If you do not want to use the mediaproxy function, remove these lines.
   # To use this directive, you need the http.cache plugin for Caddy.
   cache {