New UI requires hostname:port for Host header

[Hazelton42]

With the new scada-LTS UI, the websocketUrl is computed by parsing the hostname and port from the Host header. When using a reverse-proxy where the address is on port 80 or 443, the browser may omit the default port and thereby leaving the header as something like: Host: scadalts.domain. In this case, the websocket URL is computed as:
http://scadalts.domain:undefined/Scada-LTS/ws-scada/alarmLevel. This leads to the "Failed to establish WebSocket connection" error message in the console.

To Reproduce
Steps to reproduce the behavior:

1. Configure a reverse proxy or update the Tomcat application to serve the application on port 80
2. Navigate to the application, log in and select the new UI icon.
3. In the browser log console observe the "Failed to establish WebSocket connection" message
4. Note that navigation using the left menu of the new UI is non-functional

Desktop (please complete the following information):

• OS: Fedora Linux
• Browser: Chrome
• Version: v2.7.6.1