check for HTTPS connection

public/install/functions.php

@@ -17,6 +17,13 @@ function checkPhpVersion()
     return "not OK";
 }
 
+function checkHTTPS()
+{
+    return
+        (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off')
+        || $_SERVER['SERVER_PORT'] == 443;
+}
+
 function getMySQLVersion()
 {
     global $requirements;

public/install/index.php

@@ -63,6 +63,7 @@ if (!isset($_GET['step'])) {
     ?>
     <p class="login-box-msg">This installer will lead you through the most crucial Steps of Controlpanel.gg`s
         setup</p>
+    <p class="<?php print(checkHTTPS() == true ? "ok" : "notok"); ?>">HTTPS is required</p>
 
     <p class="<?php print(checkPhpVersion() === "OK" ? "ok" : "notok"); ?>"> php
         version: <?php echo phpversion(); ?> (required <?php echo $requirements["php"]; ?>)</p>