Merge branch 'wiki_security_headers' into 'master'

Configure mediawiki's security headers

See merge request !278

roles/archwiki/templates/LocalSettings.php.j2

@@ -57,3 +57,7 @@ $wgMainCacheType = CACHE_MEMCACHED;
 $wgParserCacheType = CACHE_MEMCACHED;
 $wgMessageCacheType = CACHE_MEMCACHED;
 $wgMemCachedServers = [ "unix://{{ archwiki_memcached_socket }}:0" ];
+
+# security headers
+$wgReferrerPolicy = ["no-referrer-when-downgrade"];
+$wgEditPageFrameOptions = "DENY";