Enable TLS for TURN traffic (#118)

src/config.ts

@@ -19,7 +19,8 @@ export default {
     ICE_SERVERS: [{
         urls: [
             'turn:turn.threema.ch:443?transport=udp',
-            'turn:turn.threema.ch:443?transport=tcp'
+            'turn:turn.threema.ch:443?transport=tcp',
+            'turns:turn.threema.ch:443',
         ],
         username: 'threema-angular',
         credential: 'Uv0LcCq3kyx6EiRwQW5jVigkhzbp70CjN2CJqzmRxG3UGIdJHSJV6tpo7Gj7YnGB',