fixes #2277 - adds spice html5 support

This also adds a newer version of the web socket proxy (where we
probably need to use an external package instead of vendor it).

we still allow users to use the old XPI based spice client (which would
ensure end to end security as well) via a 'new window' button....

Adds VNC support within the browser

At first, this allows to view oVirt managed hosts within foreman.