websocket ip from config to web client

[rkjdid]

right now the listenaddr specified in the config is passed to the html template, which is in turn used by the web-client for opening the websocket connection.

This is not needed, the client can simply re-use window.location.href instead which is simpler and also allows for ListenAddr to be set to 0.0.0.0 (which right now breaks the websocket)

thanks @krossov for reporting