[moodle] Configure cookies to be HttpOnly

This is done with the cookiehttponly config set to 1.

dd-ctl

@@ -498,6 +498,7 @@ setup_moodle(){
 	php7 admin/cli/cfg.php --name=enablemobilewebservice --set=0
 	php7 admin/cli/cfg.php --name=enablebadges --set=0
 	php7 admin/cli/cfg.php --name=timezone --set="${MOODLE_TIMEZONE-Europe/Madrid}"
+	php7 admin/cli/cfg.php --name=cookiehttponly --set=1
 	php7 admin/cli/purge_caches.php
 	EOF
 }