Add an explicit tunnel timeout configuration option to increase the
tunnel timeout for persistent socket connections from two minutes (2m)
to one hour (3600s). A configuration was already present to apply a
tunnel timeout to the zaqar_ws endpoint, but that only applies to
connections made directly to the zaqar_ws endpoint directly. Since UI
now uses mod_proxy to proxy WebSocket connections for Zaqar, the timeout
is now applied for the same reasons to the ui haproxy server.