Use only SPICE for display
There were stakeholders that wanted us to pursue a route where Boxes could work without SPICE. For this reason the VNC display was kept around and offered as a fallback for when SPICE is not available in the build environment.
As of now we have decided that Boxes should be a single display protocol tool for simplicity, and that SPICE should be only removed when there's a drop-in replacement with feature parity.
I really don't want to go down the route of supporting multiple protocols again.