TT#73752 use cookie_secure=1 for sessions

If this attribute set to 1 (or true for backward compatibility) - the
    cookie send by the server to the client will got the secure flag that
    tells the browser to send this cookies back to the server only via
    HTTPS.

Change-Id: Ia99bf2187965893d14f7fed7f7c11c0b016aea53

lib/NGCP/Panel.pm

@@ -121,6 +121,7 @@ __PACKAGE__->config(
     'Plugin::Session' => {
         flash_to_stash => 1,
         expires => 3600,
+        cookie_secure => 1,
     },
 
     'Plugin::Authentication' => {